A Carter Thermo-Quad Guide

Author: Gary Lewallen (aka. Vaanth)
Date: 24 February 1998

Copyright 1998 Gary Lewallen



The Carter Thermo-Quad is a four-barrel carburetor with a spreadbore throttle bore configuration. It was designed as an emissions capable carburetor that retained or surpassed secondary throttle performance of earlier Carter carburetors, while delivering superior primary fuel economy. The Thermo-Quad consists of three main sub-assemblies, an aluminum fuel bowl cover, a phenolic resin main body, and an aluminum throttle base assembly. The Thermo-Quad derives its name from the phenolic main body. Due to the material of the body, the carburetor bowl can stay 20 degrees cooler than an all metal carburetor in the same environment. The Thermo-Quad was used by Chrysler Corporation in cars and trucks 1971-1984. Aftermarket versions were also produced by Carter.

This guide is intended to provide information for identifying Thermo-Quad carburetors and related items. It provides a basic history and basic descriptions of the carburetor and its subsystems. It is not intended as a full theory of operation manual nor a repair manual. Service documentation should be consulted for repair procedures and service details. The factory service manuals provide good service procedures and theory for specific models. Other sources may be consulted for general repair and modification procedures as well as theory of operation. See the list of references for sources.

This guide is written with carburetor 'swapping' in mind. Thus, certain items are discussed with modification consideration (ie. emission subsystem disablement) with the intent for adapting a non-original carburetor and/or enhancing performance. The modification and adaptation of the carburetors may present legal issues, so consider the interest of any appropriate government(s).

History and Description...


The Thermo-Quad (TQ) was initially released for competition in 1969. Chrysler introduced the TQ on the 1971 340. The first series of TQs including the 71 340 version and the Competition Series TQs were air metered units unlike like the 72 and later TQs which were solid (liquid) fuel metered. The Competition Series (CS) were available in 850 cfm and 1000 cfm ratings. CS units use a manual choke and have a minimal amount of external attachments compared to OEM production units. The CS was discontinued in the mid-70s. Carter released the 9000 series in the latter 70s as replacement carburetors for Chrysler and GM Quadrajet applications. The 9000 series was very similar to the production Chrysler Thermo-Quads.

In 1972, the OEM Chrysler TQs changed to the solid fuel metering type. The TQ coverage was expanded to include the 400 engine. By 1973, all Chrysler 4-bbl applications were TQs (except some 413 truck models which continued to use a Holley carburetor). As the years progressed, the TQ evolved to meet the continually tightening emissions requirements. The changes were numerous. Many features were added or modified externally and internally. The late 70s contained many variations for the various geographic regions, the various features included/excluded, and the range of applications and engines produced. Into the 80s, the TQ became more complex, but year to year major variation lessened somewhat. In 1973, TQs received a port on the base for canister purge and a port on the main body to provide a venturi vacuum signal for EGR applications. 1975 saw the introduction of the Idle Enrichment system, Altitude Compensator on some models, and the Throttle Position Solenoid for the new catalytic converter equipped cars.

In 1976, Chrysler introduced Lean Burn ignition and the TQ was modified to produce and run on a very lean air/fuel mixture. An external idle stop switch and throttle position transducer were added. In 1978, the TQ bowl vent was modified with the addition of an electric Bowl Vent solenoid. An additional rear base port for the vent hose replaced the bowl vent port. The fuel inlet moved to the rear center of the carburetor from the previous rear side location. Lean Burn became Electronic Spark Advance (ESA) in 1979. The very lean mixture idea was abandoned, but the electronic control of the ignition advance was retained. Hidden mixture screws were a feature starting with some 1980 model TQs. 1981 introduced a riveted cover for the choke pull-off linkage to prevent tampering and the oxygen feedback solenoid on some models. Idle Enrichment and Altitude Compensator was not used on feedback models. 82-84 did not change much more in a major way. The canister purge was eliminated by 84 in some applications and a power brake port was added to the rear base.

After 1984, Chrysler stopped using Thermo-Quads. Instead, the Rochester Quadrajet was used through 1989 on cars and until 1988 in trucks when Electronic Fuel Injection replaced them. Carter continued to supply the fuel pumps for the Quadrajet equipped vehicles. Although Chrysler was the primary manufacturer to use the TQ, International Harvester (IHC) used them in the late 70s and Ford used them in 1974.

The Thermo-Quad was available with two primary throttle bore sizes, 1-3/8" and 1-1/2". Flow ratings (CFM) vary depending on the source, but the TQs with the 1-3/8" bores are listed as 750-800 CFM and those with the 1-1/2" primary throttle bores are rated at 800-850 CFM. All TQs have the 2-1/4" diameter secondary throttle plates. The primary bore size depended on application. In general, all 78 and later 318s and 360s and all 340s had the smaller bore. Earlier 360s varied depending on application, most 400s and all 440s had the large bore. The 9000 series have the small primary bore and were rated by Carter at 800 cfm. Later TQs (ie, Lean Burn and ESA applications, feedback systems) are quoted with less flow ratings, but this is due to the control of the carburetion system, not the inherent flow capability of the basic carburetor. The internal metering is set for leaner running conditions for Lean Burn. Either bore size can be tuned to run well on most engine combinations. The smaller bore offers a slight increase throttle response but less overall flow. The different bore sizing, ie. spreadbore, is an aspect that can lead to increased fuel economy while delivering similar wide open throttle (WOT) performance to an equivalent standard bore configuration. The adjustability of the TQ and the spreadbore configuration allows the use of a large CFM carburetor on a small displacement engine.

The TQ gets its name from the phenolic resin main body. This is "sand- wiched" between the aluminum bowl cover assembly and the lower throttle flange assembly. The plastic body keeps the fuel ~20 degrees cooler than an all metal carb in the same environment, leading to less percolation problems and increased performance due to a denser charge. The TQ is a metering rod based carburetor like other Carters (AFB, AVS, BBD). The primary jets are housed in the plastic body, the primary metering rods are suspended from the cover mounted step-up piston assembly into the jets (in the 71 TQ and the CS, the primary jets are also housed in the cover). Engine vacuum (related to load) controls the position of the metering rod in the jet, metering the fuel flow. The secondary jets are suspended from the cover. Secondary flow is controlled by variable venturi effect in the secondary bores. The TQ secondary throttle plates are controlled by direct mechanical linkage, air flow is controlled by a secondary, spring tension resisted, air valve. The valve is further controlled and damped by the choke pull-off diaphragm.

The OEM TQs have a divorced choke (73-up with electric assist in most applications), the 9000 series have an integral electric choke, and the CS were equipped with a manual choke. All OEM TQs and later CS have screw-in jets. Early CS retained the jets via O-rings.


To identify TQs, the model number is stamped on the lower left rear bolt flange. Earlier TQs also had a tag under one of the front bowl cover screws, later ones have a bar code sticker on the bowl cover with the Carter model and/or a Chrysler part number. International Harvester TQs also have a tag under a front bowl cover screw.

Additional numbers will be found on the carburetor sections. These numbers are not used for TQ identification, but some can be used to relate one casting to the other (note that parts with the same casting number may be machined differently). The upper bowl cover has the casting number on the top, right of center rear: 6-XXXX (example: 6-2141, 6-2080, 6-2024). The bowl has the casting number molded on the bottom of the right bowl near the front, it is difficult to see with the throttle base on the carb: 0-XXXX (example: 0-2511A, 0-1823, 0-2709A). The throttle base has the casting number on the right upper side in a small recess: 1-XXXX (example: 1-2357, 1-2294, 1-2967. More numbers will be found ink stamped, cast or stamped in various areas. Moreover, numbers are usually stamped below the model number on the lower left rear bolt flange. The model number consists of four digits, usually followed by an 'S' (ie. 6318S). The model number is the primary and documented identifier.

The 71 OEM units can be identified externally by the mixture screws which protrude at an angle from the base, in the same plane as the base, later units protrude perpendicular to the base plane, but angle upwards from it. Note: some 1980 and later units have hidden mixture screws. The Competition Series have raised pads on the upper bowl cover for a label. Also, the CS have minimal external attachments, such as the lack of a PCV port. The mixture screws are similar to the 71 OEM TQs.

The fuel inlet on the CS and the 78-84 OEM units was located in the rear center and the 71-77 OEM and 9000 series have the fuel inlet on the right rear side. The aftermarket 9000 series were available in 4 models: 9801, 9811, 9800, 9810. The 9801, 9811 have Chrysler linkage (9801/9811 is EGR capable). Note: later OEM TQs model number started with a 9 as well, but are not to be confused with the aftermarket 9000 series.

TQs with 1-3/8" primary throttle bore will have '2-315' stamped on the throttle plates. 1-1/2" units will have '2-314' stamped on the plates. All secondary plates are stamped with '2-312'.


This section briefly describes the primary Thermo-Quad subsystems that are readily accessible and the various attachments for emissions. For detailed theory of operation of the subsystems or general operating functions such as the low and high speed metering circuits, refer to the references listed in the References section, specifically the Carter Thermo-Quad service manual. See the Service Parts Information section for details on parts and part numbers.
jets are contained in the primary and secondary circuits, one for each barrel. Early CS units had press-in jets retained by o-rings. CS and 71 TQs have the primary jets in the upper bowl cover. All other TQs have screw-in primary jets in the main body. All TQs have the secondary jets mounted in the upper bowl cover. All jets have a part number prefix of 120-. 72 and later TQs usually have the part suffix stamped on the jet, primaries: 4XXX, secondaries: 5XXX (or 120-5XXX). The XXX denotes the size, example: 4098 = 0.098", 5137 = 0.137". CS and 71 TQs have part number suffixes of 3XX or 3XXX.

Metering rods and step-up:
metering rods meter the fuel through the primary jets. They are essentially controlled by engine vacuum and a mechanical link, step-up cam/lever, connected to the primary throttle shaft. Many variations of metering rods were available through the years. The depth of pre-76 models could be adjusted to tune, ( primarily ), cruising condition flow via a screw adjustment. Some later models retained this feature, but starting in 1980 may have the adjustment locked via a collar. Metering rods have three steps for metering, economy, midrange, power. They are usually stamped with a part number, 75-XXXX or XXXX where the XXXX defines the step sizes. The CS and 71 TQs have numbers 16-XXX.

TQs are a single fed, dual inlet, dual bowl carburetor. One bowl feeds each carb half, ie. one primary and one secondary. The dual bowl arrangement is contained in the phenolic main body. Dual floats and dual inlet valves are employed. Early TQs used brass floats. Later models (73-74 and later) use nitrophyl floats. All OEM TQs are equipped with needle & seat number 25-1086 (0.0935" orifice).

Accelerator pump:
the accelerator pump is located on the left front and feeds from the left fuel bowl. The pump is activated by the left side throttle bracket. There is some stroke adjustability at the upper lever. The fuel is transferred via a plastic tube internally to the squirter which resides above the primary venturi. Later models have two adjustment holes instead of three, and perform a two stage pump that add additional fuel as the secondaries open. Three accelerator pump clusters (squirters) were available.

Secondary air valve:
TQ secondary throttle plates are mechanically linked to the primary on the left side. As the plates begin to open, the secondary air valve senses the opening and begins to open to provide air flow which starts fuel flow from the secondary jets. The initial opening and rate is determined by a counteracting tension spring inside the cover. The opening is additionally regulated and dampened by the choke pull-off assembly. The air valve is contoured and the movement provides a variable venturi effect. A secondary fixed baffle is mounted below the air valve. Total air valve movement is limited by a protruding tab. The counteracting spring tension is adjustable via a slot/lock screw on the left side to tune the rate. Carter designed a special tool to facilitate this adjustment. Some of the CS TQs used an adjustment and lock screw arrangement similar to the AVS.

OEM TQs use a divorced, manifold mounted choke. Exhaust crossover heat operates the thermostatic spring contained in the choke well. Most 73-84 TQs were electrically assist heated. The electric control is via a small module mounted to the intake or right head. This unit times the assist based on temperature and time and receives power from the ignition run circuit. 9000 series have an integral choke assembly identified by the black, circular plastic thermostat housing. This unit is electrically controlled. CS units have a manual choke. Choke action is accomplished via the choke plate in the top of the primary side.

Mixture screws:
screws used through 11976 had a 20 degree taper at the seat. In 1977, this was changed to 12 degrees to reduce adjustment sensitivity. Some ~77-79 TQs also contained internal restrictors to limit adjustment. Plastic caps with tabs to limit adjustment were also installed on several models. Many 1980 and later TQs had the base redesigned to enclose the mixture screws so they could be 'capped' via plugs after factory setting.

Choke pull-off:
All TQ models. This performs the vacuum kick pull-off function for the choke at initial cold engine start. It is also used to regulate and dampen secondary air valve opening. Mounted on the right rear base under a mounting bolt and screw. Connects to the rear vacuum port, right, color code gold. The CS has the diaphragm for secondary air valve control only.

Hot Idle Compensator:
Some models are equipped with a compensator to allow extra air into the mixture during high heat conditions. If equipped, it is located on the bowl cover over the secondary air valve. High temperatures can create an over-rich idle condition, and this compensates for it, by allow extra air flow when it opens.

Idle Stop Solenoid (ISS):
71-76. Used to set the idle higher than the basic curb idle screw for emissions reduction and to allow further closure of the throttle blades at engine shutdown to prevent 'dieseling' or 'run-on'. Mounts on a bracket retained by base mounting bolt and screw on the right side for 72-76. 71 mounted to the left side of the intake under the carb linkage.

Exhaust Gas Recirculation (EGR) port:
73-84, not used in some 76~81. Some located on the main phenolic body as a tap into the venturi for vacuum signal. Venturi port is connected to a vacuum amplifier if used. Some models use a ported signal via a base port on the right front. Base ports color coded black. Venturi ports are brass.

Evaporative Control System (ECS) port:
73-84. Used to purge the ECS charcoal canister of collected gas fumes from the bowl vent and fuel tank vent. Color coded red.

Idle Enrichment (IE) system:
75-81. This is a driveability enhancement. It supplements the choke function by allowing an even richer mixture during the warm up period to improve driveability. This will appear as a small attachment on the front bowl cover that has a vacuum port that connects to a coolant temperature sensor (CCIE), then to manifold vacuum with bleed. It will also be plumbed into the EGR delay timing system.

Altitude Compensator or Alcomp (Alc):
75-81. This is another driveability enhancement. It appeared on most California and Federal high altitude cars. It appears as a small cylinder attached to the front of the Idle Enrichment system at the front of the bowl cover. A small bellows inside reacts to altitude changes and alters the air flow in the high speed metering circuit. This improves driveability and reduces emissions by maintaining a correct fuel/air mixture. Note: later vehicles may be equipped with a remote Alcomp sensor (fender well) to signal the feedback solenoid controller to compensate.

Bowl Vent (BV) solenoid:
78-84. In an effort to completely capture all fuel bowl evaporative emissions, the standard bowl vent was redesigned with a two way valve and holding solenoid at the rear of the carburetor. When the engine starts, manifold vacuum pulls the valve rubber 'puck' down, opening the bowl to the canister port. The solenoid is connected to the ignition run circuit and holds the valve open during low vacuum periods while running. When the engine is shutdown, the valve releases and reseals the float bowl. Connects to rear base port, color code gold.

Ground Switch:
76-84. This appeared with Lean Burn (LB). It signals the computer that the throttle plates are at idle position. Later models with solenoid idle stop combined the functions. It is located on the bracket on the right front. A throttle shaft attachment contacts it.

Throttle Position Transducer (TPT):
776-81. This appeared with Lean Burn. It signals the position and movement rate of the throttle to the computer. It is attached via the same bracket as the Ground Switch.

Solenoid Idle Stop (SIS):
81-84. Used to set the idle higher than the basic curb idle when additional heavy accessory load (ie. rear window defogger, air conditioning) is placed on the engine. Mounts on a bracket on the right front.

Some models, primarily trucks, may have a dashpot to slow throttle closing rate to reduce stalling. Mounted on a bracket on the left front.

Vacuum Pull-Off Choke:
A few models may have an additional pull-off mounted on the left rear. This connects to manifold vacuum via a control switch in the vacuum plumbing. It prevents choke operation after engine warm up.

Throttle Position Solenoid (TPS):
75--later, some models. Mounts in the same place as the idle solenoids and is used to delay full throttle closure at deceleration to prevent a momentary rich condition thus protecting the catalytic converter(s).

Vacuum Throttle Positioner (VTP):
75--later, some models. Mounts in the same place and performs the same function as the Throttle Position Solenoid. Also serves as a speed sensor.

Pulse Solenoid, Oxygen Feedback Control (O2):
81-84. Mounts on the front of the bowl cover (where the IE module mounted earlier). This solenoid is used to control the air/fuel mixture via varying duty cycle pulsing from the control computer based on feedback from exhaust, engine, and ambient sensors.

Fuel bowl inserts:
some later models had an insert in the fuel bowls to reduce the bowl fuel volume.

Choke pull-off cover:
many 81-84 models have a cover to prevent field adjustment of the pull-off.

Port Diagram

This section contains a diagram and notes to identify the various hose port connections on the Thermo-Quad. Different port configurations were used throughout the years. The diagram is a representation of the throttle base, top view. It is drawn with all possible ports. The label notes identify the ports and their general usage. Some ports are contained in the bowl or bowl cover. These are also identified. The ports are labeled by (x)...descriptions follow the diagram.


                              ___     _         
                        (B)  |   |   | |
                    ||  ||   |   |   | |    ||   //(F)
                    ||  ||   |   |   | |    ||  //
            | O     (A)      (C)*    (D)    (E)   O |     /|
            |                                       |    / |(G)
            |                                       |   /  |
            |        -----             -----        |---  /
            |       /     \           /     \       |    /
            |      |       |         |       |      |---
           =|      |=O===O=|         |=O===O=|      |=
            |      |       |         |       |      |
            |       \     /           \     /       |
            |        -----             -----        |
            |      -----------     -----------      |
            |     /           \   /           \     |
            |    |             | |             |    |
            |    |             | |             |    |
           =|    |===O=====O===| |===O=====O===|    |
            |    |             | |             |    |
            |    |             | |             |    |
            |     \           /   \           /     |
            |      -----------     -----------      |
            |                                       |
            |                                       |
            |                                       |
            | O (H)  (I)  (J)  (K)    (L)         O |
             ---||--|---|-||--|---|---||------------   -------
                ||  |   | ||  |   |   ||               \     /
                ||  |   | ||  |   |   ||                -----
                    /   /     |   |                      //
                   /   /      |   |                       (M)
                  /   /       |   |
                  ---         |   |


Choices and Adaptations:


Chrysler used the TQ from 1971-1984. Ford used it in 1974 on some 460s and International Harvester used it in 74, 75, 79, 80 on 345/392 engines. The CS series was available from 69-~73. The aftermarket 9000 series was available from ~76-~late 80s. The best OEM years to locate are 72-75. TQs from this period have the least emission control add-ons. The 71 OEM TQ performs well and has minimal emission considerations. Due to its air metered design, it is unlike the later TQs and few parts are still available for it. The CS TQ was not intended for street use, thus it lacks provisions for many street engine items. Carter released the 9000 series in the latter 70s. It is a good unit for most applications. It is the same design as the OEM TQ with minimal emissions devices. In 76, Chrysler introduced Lean Burn (ELB) which evolved into Electronic Spark Advance (ESA). The 76-80 carburetors can be adapted for use in earlier vehicles. Many will need idle screws and vacuum ports added. Most 78 and later TQs use a more complex bowl venting arrangement. The IHC carburetors are fairly simple like pre-76 Chrysler TQs. 1980 TQs began began receiving a pulsing solenoid as part of an oxygen sensor feedback system to allow more computer control of the mixture. The TQs from this period are the most complex and least desirable units.

There were several internal metering and passage changes that occurred over the years for emissions. Most TQs can be tuned to match most applications. The later carbs, however, will need extra adaptation for earlier vehicles.

The Competition Series carbs should generally be avoided except for racing. The aftermarket 9000 series were available in 4 models: 9801, 9811, 9800, and 9810. The 9801, 9811 have Chrysler linkage (9811 is EGR capable). Note: later OEM TQs model number started with 9 as well, not to be confused with the 9000 series. The 9801/9811 is the preferred aftermarket TQ.

Because TQs are out of production (since 1985), new parts are scarce except for common service items. Kits are available through Carter, Hygrade, KEM, etc. Floats, choke pull-offs, choke assemblies are also available. Tuning parts, ie. jets, rods, are no longer available new. Carter did make rod/jet kits ( Strip Kit ), but they are discontinued. Because replacement jets and rods are no longer available, tuning can be limited, unless a supply of used rods and jets is obtained. Many variations were used in the various applications over the years. Jets and rods can be modified. The carburetors are easy to rebuild. TQs usually work well with just normal service adjustments.


Note: for tuning basics and repair procedures see the References section for possible information sources. This section considers basic and emission subsystem adaptation possibilities.

TQ on 'squarebore' intake:
the TQ requires a spreadbore intake manifold. It can be adapted to a squarebore type via the use of an adaptor. Several companies make these (see Service Parts section). Some performance can be lost compared to a comparable spreadbore intake depending on the quality of the adaptor and the transition area. Vacuum leaks can be an issue too.

1-3/8" vs. 1-1/2":
The TQs have two different primary bore sizes. These units can be interchanged. The smaller bore will yield slightly better throttle response, but less overall flow.

The jets and metering rods's can be changed on the TQ to tune its performance. Many sizes were available. See the Service Parts section for sizing information. Many later model TQs were lean on the primary side. Increasing primary jet size and/or reducing metering rod size will richen the primary side. Secondary jets can be changed as well. If replacement units are not available, jets may be drilled to increase size. Rods may be filed to reduce size. Solder and drilling/filing can be used to reverse this to some extent.

Early TQs had brass floats. By 1975, all TQs used nitrophyl floats. Over time, the nitrophyl floats can absorb gas and sink, allowing fuel levels to be too high. The floats should weigh 7.4-8.0 grams. Carter no longer services brass floats, but several sources are available (see the Service Parts Information section).

Accelerator pump clusters (squirters):
The accelerator pump clusters were available in various sizes. Drilling may be used to increase the orifices to tune pump fuel delivery.

Mixture screws:
the screws are readily accessible on 71-79 TQs. Some of these had plastic caps to limit travel. The caps can be removed. Some ~77-79 contained internal restrictors to mixture adjustment. These restrictions are in the base mixture path from the idle circuits and could be opened if needed. Note: mixture screws prior to 1976 had a 20 degree taper at the seat and cannot be interchanged with 77 and later 12 degree screws. 1980 and later TQs may have hidden screws. The base enclosed the screws in cast protrusions under press-in caps. The caps may be removed for mixture adjustment.

Interchanging bases, fuel bowls, upper bowl covers:
The three main TQ sections are matched for each applications. Most will interchange mechanically, but flow and metering characteristics may not match. The sections have casting numbers that will allow some interchange identity, but the casting machine work for applications may vary.

Evaporative Control System (ECS):
73 and later will have an extra base port for the charcoal canister purge. This is not a parasitic device and may be retained without decreasing performance. The bowl vent is plumbed to the canister to vent fumes. The purge pulls these fumes and those collected from the tank. The purge port can be capped to disable it.

Exhaust Gas Recirculation (EGR):
EGR occurs outside of the carburetor, but tuning and vacuum source provisions are incorporated into the various TQs used on EGR equipped vehicles. The tuning is usually not a major issue. TQs may provide a venturi or a front base port for EGR vacuum signals. If EGR is not used, these ports can be capped.

Idle Enrichment system (IE):
this system is a driveability enhancement. It allows a richer mixture during the warm up period to improve driveability. It supplements the choke function by blocking part of the air bleed to richen it. The TQ with IE will have a small attachment on the front bowl cover that has a vacuum port that connects to a coolant temperature sensor (CCIE), then to manifold vacuum. It is also integrated into the EGR delay circuit. The IE port can be retained or capped (if capped, the carb behaves normally).

Altitude Compensator (Alcomp...Alc):
This device alters the high speed metering circuit by sensing atmospheric pressure. It mounts to the same area as the IE system at the front of the bowl cover. This system is also a driveability enhancement, which also reduces emissions, by allowing the TQ to compensate for elevation. It could be disabled by blocking the air passage ports (or the front vent pipe) to allow a normal full rich condition for the high speed circuit.

Solenoid Bowl Vent (BV):
Most 1978 and later TQs have an electric bowl vent solenoid that replaces the earlier mechanical vent. 72-77 TQs used a linkage actuated bowl mounted vent that fed to the ECS charcoal canister. 71 TQs actuated the same way, but vented to the oil breather or the atmosphere. The later units vented through the rear base. The vent mechanism closes to vent to the ECS canister with the engine off. When started, engine vacuum opens the vent and the electric solenoid is powered to hold the vent open during low vacuum conditions. The electric power is supplied by the ignition run circuit. While running, or off-idle for earlier TQs, the bowls vent inside the air cleaner. Vents should be retained for all types. The solenoid bowl vent could be redesigned to eliminate the solenoid by adapting earlier parts, but the remachining effort is not worth the result. The solenoid bowl vent system can be retained by wiring into the ignition run circuit if adding to an earlier vehicle. If the ECS canister is not used the port can be vented to the atmosphere like 70 and earlier carburetors were done. A protective screen over the port can be used.

Oxygen Feedback Pulsing Solenoid (O2):
Most 1980 and later TQs will contain an oxygen feedback controlled, pulsed solenoid in place of an IE module. The solenoid is variably pulsed by the control computer based on the signal it receives from the exhaust mounted sensor. The solenoid alters the variable air bleeds by inputting more or less air based on computer signal duty cycle. If the solenoid is disconnected, the air bleeds will allow a full rich condition. Tuning with this in mind, this TQ could potentially be used in a non-control/feedback vehicle.

Idle Stop Solenoid (ISS):
the idle stop is external to the TQ and is used to prevent engine run-on. It can be retained, disconnected, or reused for other functions such as compensating for engine loading (ie. air conditioning) like a SIS unit.

Solenoid Idle Stop (SIS):
the idle stop is external to the TQ and is used to compensate for engine loading (ie. air conditioning). It can be removed if not needed.

Throttle Position Solenoid (TPS):
the solenoid is external to the TQ and is used for catalytic converter protection. It can be removed if not needed.

Vacuum Throttle Positioner (VTP):
the positioner is external to the TQ and is used for catalytic converter protection and/or a speed sensor. It can be removed if not needed.

Throttle Position Transducer (TPT):
the positioner is external to the TQ and is used to signal throttle position and movement rate to the computer. It can be removed if not needed.

Ground Switch:
the switch is externally to the TQ and is used to signal throttle closed to the computer. It can be removed if not needed for a computer or for idle adjustment.

Idle screw adjustment on ELB and ESA TTQs:
Lean Burn carburetor idle speed is controlled with the curb idle adjustment screw that contacts the "throttle closed switch contact". This contact signals the Spark Control Computer that the engine is at idle, or not. The contact is mounted on a bracket on the passenger side of the carburetor. There is also a transducer, but it is to sense throttle position and opening rate. Some had the conventional idle screw based on application. There are two approaches to the idle adjustment... 1) retain the "throttle closed switch contact" bracket (on the passenger side) and adjust the idle there...this was the factory curb idle adjustment. 2) Drill and tap the boss for the conventional idle screw. Drill the boss perpendicular and near the center, but align the hole with the throttle bracket extension. The factory screw size is 10-32. This approach yields an idle adjustment screw like earlier TQs had.

Adding vacuum advance port to ELB and ESA TQs:
Many Lean Burn carburetors lack a vacuum advance port because advance was controlled by the ELB computer. The port may be added to provide a vacuum advance signal for a conventional non-ELB/ESA distributor system. The vacuum advance port is somewhat tricky and is best performed by comparison to an earlier throttle base that has the factory port. Using ~5/32" drill bit, drill the throttle base where the vacuum port existed on previous units....drill into the open (roughly square) opening between the outside and the throttle bore. This will accommodate the vacuum fitting. Then, using ~1/16" drill bit, drill two holes just above the throttle plate into the same square opening from the throttle bore side one hole adjacent to the other parallel to the throttle plate. Then, using a knife or small screwdriver, blend the holes together into a slot. This serves as the off-idle transfer slot to feed the vacuum port. Press a short length of 5/32" pipe or an old fitting into the outside hole. Vacuum advance is now available. Using another base with the port as a guide will ensure proper placement of the transfer slot. Misplacing the vacuum idle transfer slot can cause an off-idle stumble and will necessitate additional tuning or replacement.

Tamper-proof choke pull-off:
TQs with this feature have a pull-off with the enclosure attached. These can be replaced with an earlier standard pull-off to allow choke tuning.

Fuel bowl inserts:
these may be removed to allow full bowl volume.

Other Considerations:

The TQ can possess the same problems as other carburetors. Some of the features of the TQ can create problems specific to its design. Common problems can usually be remedied with standard repair and tuning practices. Some specific considerations are discussed in this section.
Main jet wells:
The primary jets in 772 and later TQs are screwed into a threaded insert in the fuel bowl bottom. This area is connected via a small plastic channel to the internal fuel pickup area. There is one channel for each jet. These channels are attached to the main body with an epoxy adhesive. The epoxy can weaken and begin leaking with age. Correction can be made by reattaching the wells with new epoxy (J-B Weld has been found to work). Remove the wells and the old epoxy. Clean the area and reattach the wells with a small bead of epoxy. Remove any surplus epoxy that may interfere with reassembly.

Bowl warpage:
Due to the phenolic material construction, the fuel bowl can warp. The area most prone to warpage is the upper edge corner of the bowl at the rear. Correction can be made by resurfacing the upper surface. A large flat file can be used to resurface for corner warpage or other irregularities. Warpage of the bottom (unlikely) may require replacement due to its configuration.

Bowl breakage:
Severe breakage may require replacement of the fuel bowl. Small breaks and cracks may be repaired with a fuel-resistant epoxy. The bottom surface has tabs for gasket location. If these break, repair is not required if the break does not extend into the bowl. Small breaks around the screw holes do not require repair if the break does not extend into other areas.

Idle transfer slot:
If the primary throttle plates are opened too far in an attempt to set the idle speed, the idle transfer slot may be exposed to the air flow. This can result in an off-idle hesitation. Correction can be made by drilling a 1/16"-1/8" hole in the forward half of each primary throttle plate. The holes allow sufficient air flow for speed setting without exposing the idle transfer slot.

Step-up piston spring:
The step-up piston spring resists vacuum pull on the piston. In cases where idle vacuum is too low to allow stable holding of the step-up piston, the spring may be trimmed to reduce its force.

Commercial rebuilders:
Carburetors that are mass rebuilt by commercial rebuilders have their useful service life shortened or ended. This usually stems from mixing parts, bad service procedures, and cleaning by tumbling or blasting. Tumbling and blasting removes the factory finishes. This leads to accelerated wear and corrosion problems. In the case of the TQ, the factory linkage was cadmium or irridite finished. The throttle shafts were Teflon coated. Tumbling or blasting removes these finishes and will lead to corroded sticking linkages and binding or leaky shafts. The TQ phenolic fuel bowl can be damaged by tumbling or blasting. Jets, rods and internal orifices are further damaged by these processes. Mixed parts without proper analysis can result in a poorly performing or useless unit. A carburetor from a rebuilder of this nature requires careful examination to determine its future usefulness.

Numeric Listing...

Listing Notes:

This section attempts to identify most Thermo-Quads by the Carter model number. There were a multitude of models available with many configurations to accommodate all the applications and varying regulations and conditions. The listing identifies the models by primary application and year model. There may be some variation in date availability and multiple application models. Most of this is reflected. Abbreviations are used to highlight specific features, particularly with California and Federal based emissions and some major emission subsystems.

Known jet and metering rod information is included for the earlier years as this was documented by Carter and Chrysler. Later years were not documented as well. A kit reference number is given for each carb. The kits are referenced in the Service Information section. The Carter 'Zip Kit' is the primary reference. Some conflicts arise in the documentation. Carter information is used where conflicts occur.

All primary and secondary jets are prefixed with 120- for TQs. All metering rods are prefixed with 75- for 72 and later OEM and 9000 series. CS and 71 TQ rods are prefixed with 16-. The prefixes are omitted from the listing to save space.

The 'Kit' field contains a code corresponding to a row code under the carb kits in the Service Parts section. The code is referenced to the Carter rebuild kit or "Zip Kit". Some competitor kit numbers have been provided. These numbers have been cross-indexed to Carter's. The cross-index is not 100% due to some manufacturer variances. The most common cross-index has been chosen in these cases.

Note that most TQ model numbers had an 'S' suffix. Many will also appear with a 'TQ' prefix. These were left out of the list to save column space. Where known, Chrysler part numbers are also listed in parenthesis.

Because the Rochester Quadrajet replaced the Thermo-Quad in 1985, a brief listing of Quadrajets follows the TQs as reference.


Automatic Transmission
Manual Transmission ( No reference means both transmissions )
Primary Jet
Secondary Jet
Primary metering rod
Primary throttle plate diameter in inches, All secondaries are 2-1/4"
High Performance
California application; generic for CA, N95
Federal application ( No reference means both Federal and California.)
Canada application. Typically, Canada used Federal carbs except noted.
Light Duty
Medium Duty
Heavy Duty
Lean Burn, ESA. Noted on 76's. After 76, most F cars were LB (N92, N94).
Idle Enrichment
Altitude Compensator. Few noted, most CA and last years had Alc (N96).
High Altitude
Bowl Vent valve
Oxygen feedback solenoid

Thermo-Quad Listing:

4846SCompetition Series 3313416151-1/28
4846SACompetition Series 308031166151-1/28
4847SCompetition Series 3313416161-1/28
4847SACompetition Series 308931166161-1/28
497271 340 MT (3512820)307431256551-3/86
497371 340 AT (3512821)307431256551-3/86
609072 400 AT F (3614139)4095513719371-1/21
613872 340 MT F (3614122)4095513719401-3/81
613972 340 AT F (3614123)4095513719401-3/81
614072 400 MT F (3614138)4095513719391-1/21
614472 340 AT Export 4095513719501-3/81
616572 400 MT CA (3614172)4095513719381-1/21
616672 400 AT CA (3614173)4095513719381-1/21
631873 340 MT F (3698327)4098513719621-3/81
631973 340 AT F (3698328)4098513719661-3/81
632073 400 HP MT F (3698332)4098513719651-1/21
632173 400 HP AT F (3698333)4098513719661-1/21
632273 440 & Truck AT F (3698334)4098512519661-1/21
632473 440 HP AT F (3698336)4098512519661-1/21
633973 340 MT CA (3698339)4098513719621-1/21
634073 340 AT CA (3698340)4098513719661-1/21
634173 400 MT CA (3698342)4098513719651-3/81
634273 400 AT CA (3698343)4098513719661-3/81
639472-73 340 AT Export ---1-3/81
641073 440 & Truck AT CA (3698319)4098512519661-1/21
641173 440 HP AT CA (3698329)4098512519661-1/21
6446M-440 Chrysler Marine (3698397)---1-1/21
645274 360 HP MT F (3751433)4098514319621-1/21
645374 360 HP AT F (3751434)4098514320051-1/21
645474 360 HP MT CA (3751435)4098514319621-1/21
645574 360 HP AT CA (3751436)4098514320051-1/21
645674 400 HP MT F (3751439)4098514319661-1/21
645774 400 HP AT F (3751440)4098514319661-1/21
645974 400 HP AT CA 4098514319661-1/21
646074 440 AT F early (3751443)4098513719661-1/21
646174 440 AT CA early (3751444)4098513720051-1/21
646274 440 HP AT F early (3751445)---1-1/21
646374 440 HP AT CA early (3751446)---1-1/21
648874 360 AT CA early (3751451)4098514319661-1/21
648974 400 AT F early (3751452)---1-1/21
649674 400 AT CA 4098514320051-1/21
650374 400 AT Export ---1-1/21
6518H-440-3 Chrysler Industrial---1-1/21
654574-77 440-1,-3 Truck F (3751472)4098513720241-1/21
655074 345, 392 AT IHC (448582C91)---1-3/81
655175 345, 392 AT IHC CA (459642C91)---1-3/81
656874 460 AT Ford CA (D4AE-BC)---1-3/87
659074 392 IHC (451872C91) ---1-3/81
659274 345, 392 MT IHC (451916C91)---1-3/81
661474 ??? 4098514319661-3/8-
661574 440-1 Truck AT 4098513720241-1/21
661674 440-1 Truck AT CA 4098513719661-1/21
900074 318 Export (3751474) ---1-3/81
900275-76 360 HP AT F IE (3830529)4095514319981-1/22
900475 360 AT CA IE early (3830531)4095512520861-1/22
900875 400 AT CA IE early (3830535)4098514319651-1/22
900975 440 AT F IE (3830536)4098513721091-1/22
901075 440 AT CA IE (3830537)4098513719651-1/22
901175 440 HP AT F IE (3830538)4099513721031-1/22
901275 440 HP AT CA IE early (3830539)4098514319651-1/22
901374 360 AT CA late (3751420)4098514319661-3/81
901474 400 AT CA late (3751419)4098514320051-1/21
901574 440 HP AT late (3830415)4098513720051-1/21
901674 440 HP AT CA late (3830416) 4098513719661-1/21
901774 440-1 Truck AT CA (3830417)4098513719661-1/21
901972-74 ??? ---1-3/81
902072-74 ??? ---1-3/81
902274 360 Truck AT CA (3830401)4098514319661-3/81
902374 440 AT F late (3830403)4098513719661-1/21
902474 440 AT CA late (3830404)4098513720051-1/21
902574 440-1 Truck AT F (3830405)4098513719661-1/21
902775 392 IHC F (461280C91)---1-3/81
902875 392 IHC CA (461281C91)---1-3/81
903475 440-1 Truck MT F (3870944)4099514319651-1/21
903575 440-1 Truck MT CA (3870945)4100512521101-1/21
903675-76 440-1 Truck AT CA (3870946)4100512521101-1/21
904675 400 AT F IE early (3830554)4099514319651-1/22
904776 360 AT F CA IE ---1-1/22
904974 440 HP AT CA late (3830864)4099514319651-1/22
905075 400 AT Can IE (3830561)4099514319651-1/21
905175 440 AT Can IE (3839562)4095512521441-1/22
905275-76 440 HP AT Can IE(3830568)4095513720241-1/22
905375 400 AT CA IE PDC-SW(3830570)4100514319651-1/22
905475-76 400 HP AT F IE (3830569)4098513720051-1/22
905576 360 AT CA IE (4006624)4096512519621-3/82
905675 400 SW AT CA IE 4099514321451-1/22
905776 400 AT Can IE 4099514319651-1/22
905876 440 AT F IE (4006631)4099513721091-1/22
905976 440 AT CA IE (4006632)4099513721451-1/22
906276 440 HP AT CA IE 4098513721531-1/22
906375 440 AT CA early 4099514319651-1/22
906476 400 AT LB 4099514319651-1/22
906575-76 ??? 4098513721091-1/22
906676 440 HP AT F IE 4099513721031-1/22
906875 400 AT CA late 4099514321451-1/22
906975 440 AT CA late 4099514321451-1/22
907275 360 AT CA late 4099514319651-1/22
907375 440 AT CA late 4098513721451-1/22
907476 400 AT CA (4006642) 4099514321451-1/22
907677 360 HP AT CA IE (4027735)4092513719381-3/82
907777 400 HP AT F (4027736)4098514321591-1/22
907877 440 AT F IE (4027737)4098513721591-1/22
908077 440 HP AT F IE (4027739)4098513721791-1/22
908177 440 HP AT CA IE 4098513719501-1/22
909377 360 HP AT F CA IE (4027742)4092514321951-3/82
909476 440 HP AT F (4006648)4099513721031-1/22
909576 440 HP AT CA (4006649)4098513721531-1/22
909677 440 Truck AT CA (4041553)4099512521101-1/21
909776 400 AT LB (4006654) 4099514320861-1/22
909976 400 AT CA late 4099514321451-1/22
910076 400 AT Can late 4099514321441-1/22
910177 440 AT CA IE (4027750)4098513722101-1/22
910277 400 HP AT F ---1-1/22
910377 400 HP AT F (4027761)4098514322111-1/22
910478 360 AT F IE BV (4041826)4092511019401-3/83
910878 400 AT Can Exp (4041836)4098514321591-1/23
910978 440 AT F IE early (4041830)---1-1/23
911078 440 AT F HA CA IE (4041831)---1-1/23
911178 440 AT Can Exp IE (4041837)---1-1/23
911278 440 HP AT IE (4041832)4098512521791-1/23
911477 440 AT Can 4098513721591-1/22
911577 360 AT Alc (4027727) 4092513719381-3/82
911678 440 Truck MD IE CA (4095406)4098513719501-1/23
911778 440 Truck HD CA (4095407)4099512521101-1/23
911878 440 Truck HD (4095423) 4098512521101-1/23
911977 440 HP AT CA (4027770)4098512519501-1/22
912378 318 Truck MT CA (4095427)4092511019971-3/83
912478 318 Truck AT CA (4095428)4092511019971-3/83
912578 360 Truck MT CA (4095429)4092511019381-3/83
912678 360 Truck AT CA (4095430)4092511019381-3/83
912777 440 AT 4098512521791-1/22
912879-80 345 AT IHC ---1-3/84
913478 360 AT F HA CA IE (4041856)4092511019961-3/83
913678 360 Mexico ---1-3/83
913778 318 AT Can Exp (4041858)4092511019981-3/83
914078 400 AT F (4041861) 4092513719971-1/23
914778 318 AT CA (4041865) 4092511019961-3/83
914878 440 HP AT CA IE ---1-1/23
914978 440 Truck MD AT CA (4095440)---1-1/23
915078 440 Truck HD AT CA (4095441)4099512521101-1/23
915178 440 Truck HD AT (4095442)4098512519981-1/23
915278 318 Truck AT LD Can 4092511019971-3/83
915378 440 HP AT CA (4041874)---1-1/23
916178 440 AT Can Exp (4041879)---1-1/23
917279 360 Truck LD MD BV IE---1-3/83
917378-79 360 Truck HD BV ---1-3/83
918078 440 AT F (4041881) ---1-1/23
918278 400 AT F (4041882) ---1-3/83
918378-79 318 Truck BV ---1-3/83
918578-79 318 Truck BV ---1-3/83
918778-79 318 Truck BV ---1-3/83
918878 400 AT Can Exp (4041892)---1-3/83
919078 440 Truck MD AT CA ---1-1/23
919378-79 360 Truck HD BV ---1-3/83
919478-79 360 Truck HD BV ---1-3/83
919579 318 AT CA IE BV (4095934)---1-3/83
919679 360 AT F IE BV (4095935)409551102210?1-3/83
919779 360 AT Can IE BV (4095936)---1-3/83
919879 360 HP AT CA IE BV (4095937)---1-3/83
920279 360 AT CA IE BV (4095939)---1-3/83
920379-80 345 AT IHC (1700004C91)4095511021441-3/84
920579-80 345 AT IHC---1-3/83
920779 360 Truck HD ---1-3/83
920878-79 360 Truck HD BV ---1-3/83
920979 360 Truck HD ---1-3/83
921078-79 360 Truck HD BV ---1-3/83
921179 440 Truck HD ---1-1/23
921279 440 Truck HD AT CA ---1-1/23
921378 440 Truck HD ---1-1/23
921478-79 440 Truck BV ---1-1/23
921578-79 ??? Truck ---1-3/83
921678-79 318 Truck BV ---1-3/83
921778-79 360 Truck HD BV ---1-3/83
921878-79 360 Truck HD BV ---1-3/83
921978-83 ??? Truck ---1-3/83
922178 440 Truck HD AT ---1-1/23
922378-79 318 Truck BV ---1-3/83
922479 360 Truck LD MD BV IE---1-3/83
922579 360 Truck LD MD BV IE---1-3/83
922679 360 Truck LD MD BV IE---1-3/83
922778-79 318 Truck BV ---1-3/83
922878-79 318 Truck BV ---1-3/83
922978-79 318 Truck BV ---1-3/83
923080 318 AT Can Exp BV (4179033)---1-3/83
923280 318 AT Can BV (4179035)---1-3/83
923480 318 AT F BV (4179037)---1-3/83
923680 360 AT Can BV (4179039)---1-3/83
923879-81 ??? Mexico ---1-3/83
924079 446 Motor Home AT * ---1-1/23
924179 446 Motor Home AT CA BV *---1-1/23
924380 318 AT Can Exp BV (4179043)---1-3/83
924480 360 AT F BV Alc (4179044)---1-3/83
924579 318 AT CA BV (4095495)---1-3/83
924679 360 AT CA BV IE (4095496)---1-3/83
924779 440 Truck AT ---1-1/23
924879 440 Truck AT CA ---1-1/23
925079 360 AT CA BV (4095978)---1-3/83
925180 360 Truck MD CA ---1-3/83
925280 360 Truck MD CA ---1-3/83
925480 318 Truck BV ---1-3/83
925580-85 360 Truck LD MD F ---1-3/83
925679 318 AT F Alc (4095979)---1-3/83
926580 360 Truck LD MD F ---1-3/83
926680 360 Truck LD MD F ---1-3/83
926879 360 Truck LD MD BV IE ---1-3/83
926978-79 318 Truck BV ---1-3/83
927078-79 318 Truck BV ---1-3/83
927178-79 318 Truck BV ---1-3/83
927279 360 Truck LD MD BV IE ---1-3/83
927379 360 Truck LD MD BV IE---1-3/83
927578-79 360 Truck HD BV ---1-3/83
927678-79 360 Truck HD BV ---1-3/83
927779 360 Truck HD ---1-3/83
927878 360 Truck HD ---1-3/83
927980 318 Truck ---1-3/83
928080-85 360 Truck LD MD F ---1-3/83
928180 360 Truck HD ---1-3/83
928381 318 AT BV F (4179132)---1-3/83
928481 318 AT BV Can Exp (4179133)---1-3/83
928880 318 Truck LD Can ---1-3/83
928980 446 Motor Home AT BV *---1-1/23
929180 446 Motor Home AT BV *---1-1/23
929280 360 Truck ---1-3/83
929381 318 AT BV F (4179145)---1-3/83
929580 318 AT BV F Alc (4179051)---1-3/83
929680 318 Truck MD HD ---1-3/83
929880 360 Truck LD MD F ---1-3/83
929980 360 Truck LD MD F ---1-3/83
930481-83 ??? Mexico ---1-3/8-
930580 360 AT F ---1-3/83
930680 318 O2 BV ---1-3/83
931181 318 Truck LD ---1-3/83
931481 360 Truck LD MD F ---1-3/83
932080 318 O2 BV ---1-3/83
932581 360 Truck LD Can ---1-3/83
932682 360 Truck LD MD F ---1-3/83
932783 360 Truck LD MD F ---1-3/83
932982 318 Truck LD ---1-3/83
933083 318 Truck LD ---1-3/83
933182 360 Truck LD MD CA Alc---1-3/83
933283 360 Truck LD MD CA Alc---1-3/83
934083-84 ??? Mexico ---1-3/83
934183 318 Truck LD ---1-3/83
934282 318 Truck BV (4287013)---1-3/83
935783 318 Truck MD HD ---1-3/83
935882 360 Truck HD ---1-3/83
935983 360 Truck HD ---1-3/83
936481-84 318 AT Can BV O2 (4179177)---1-3/83
936583 318 Truck LD ---1-3/83
936684 360 Truck LD MD F ---1-3/83
936783 318 Truck LD ---1-3/83
936883 318 Truck LD ---1-3/83
936984 360 Truck LD MD CA Alc---1-3/83
937084 360 Truck HD ---1-3/83
937184 318 Truck MD HD ---1-3/83
937281-82 318 AT F BV O2 (4179179)---1-3/83
937381 318 AT CA BV O2 (4179180)---1-3/83
937482-83 318 BV O2 ---1-3/83
937582 318 Truck BV (4241752)---1-3/83
937682 360 Truck BV CA (4241753)---1-3/83
937983 360 Truck BV F (4287016)---1-3/83
938079-84 ??? Mexico ---1-3/8-
938582-83 318 BV O2 ---1-3/83
938684 360 Truck BV Alc ---1-3/83
938784 360 Truck BV ---1-3/83
938883 318 AT BV O2 ---1-3/83
938984 318 AT BV O2 (4300012)---1-3/83
939184 318 AT BV O2 HA (4300019)---1-3/83
98009000 series, GM 4095513721101-3/85
98019000 series, Chrysler 4095512521101-3/85
98109000 series, GM, EGR 4095513721101-3/85
98119000 series, Chrysler, EGR4097512523851-3/85
* Note: The 446 engine used in 79-81 Dodge motor homes was built by IHC.

Rochester Quadrajet (M4ME & E4ME) Listing:

Note: O2 denotes the E4ME feedback unit.
Note: identification number is stamped vertically on the left side near the secondary throttle lever.

1708540785-87 318 O2
1708540886 360 Truck AT F (4306408)
1708540986 360 Truck AT F HA (4306409)
1708541185 318 Can Exp
1708541186-87 318 (4306411)
1708541485-88 360 Truck HD
1708541585 360 Truck HD
1708541685-88 360 Truck
1708541786 360 Truck MT F (4306417)
1708542586 360 Truck F (4306425)
1708543186 360 Truck HD CA Can (4306431)
1708543285-88 360 Truck HD
1708543385-89 318 O2 (4306433)
1708543486 360 Truck F (4306434)
1708717585-88 360 Truck
1708717685-88 360 Truck
1708717785-88 360 Truck
1708724585-88 360 Truck HD

Service Parts Information...

Metering Rod Info (dimensions in inches):

16-XXX is for 71 OEM and CS TQs. 75-XXXX is for 72 OEM and 9000 series. Step sizes listed, Econ = economy, Mid = midrange, Power = power steps.

Rod #EconMidPowerNotes
16-615.059--.040For CS only.
16-616.064--.030For CS only.
16-632.057--.040For CS only.
16-633.055--.040For CS only.
16-634.062--.030For CS only.
16-635.060--.030For CS only.
16-655.062--.040For 71 OEM TQ only.
16-683.060--.035For 71 OEM TQ only.
16-683.058--.035For 71 OEM TQ only.

Primary Jet Info (dimensions in inches):

120-3XXX is for 71 OEM and CS with screw-in jets. 120-3XX is for CS with press-in jets. 120-4XXX is for 72 and later solid fuel OEM & 9000 series.

Jet #Size
120-4092.092 *
120-4095.095 *
120-4098.098 *
120-4100.100 *
120-4101.101 *
120-4104.104 *
* denotes part of 10-203 Strip kit.

Secondary Jet Info (dimensions in inches):

120-3XXX is for 71 OEM and CS with screw-in jets. 120-3XX is for CS with press-in jets. 120-5XXX is for 72 and later solid fuel OEM & 9000 series.

Jet #Size
120-5131.131 *
120-5137.137 *
120-5143.143 *
120-5149.149 *
* denotes part of 10-203 Strip kit.

Needle and Seat Info (dimensions in inches):

Needle/Seat #Size
25-1068.111 For CS only.
25-1069.120 For CS only.
25-1070.125 For CS only.
25-1086.0935 * (stock OEM)
25-1103.111 *
* denotes part of 10-203 Strip kit.

Accelerator Pump Cluster (squirter) Info (dimensions in inches):

Cluster #Size
48-369s.031 *
48-370s.035 *
48-374s.075 *
121-662 gasket *
* denotes part of 48-380U package.

Carb Kits (Zip Kits):

RefCarterHygradeKemB-W IlkEchlinChrysler
7902-30967615554A------15554ACT-1062 **
85153x ------------------
* 902-318A is for the 9000 series, Hygrade 657C is known to work in a 9811.
** CT-1062 is the Motorcraft number for the Ford application.

Carter Strip Kit:

Carter 10-104 Strip Kit (Competition Series)
Carter 10-105 Strip Kit (Competition Series...SA)
Carter 10-110 Strip Kit (71 and Competition Series)
Carter 10-203 Strip Kit (72-up) (see Strip Kit section for early versions)


Carter 21-252 (nitrophyl), 21-249 (brass)
Chrysler 3780155
IHC 501288-C1
Ford D4AZ-9550-B, CM2028
KEM F104 (brass)
Borg Warner CF252B (brass), CF252 (nitrophyl)
Echlin Fuel Systems 2-483 (brass), 2-427 (nitrophyl)
FILKO 19-105 (brass)
Motorcraft CM-4384 (brass)
Hygrade FL4 (nitrophyl)


Note: Most of the Chrysler TQ chokes were of the same basic design. In 1973, electric assist was added. Following is a summary of most of the chokes with model applications. Various versions were available due to operating environments and emissions. The listing is per Carter choke numbers from their catalog. Some manufacturer cross-indexing differs. Chrysler and Hygrade listed for reference....

Carter 170-148. Chrysler 3512875:

Carter 170-245:

Carter 170-1371. Chrysler 4287004. Hygrade CV400 (non-electric assist):
9379 (Canada)

Carter 170-1408. Chrysler 3698355,3751484,4027715,4027793,4095328. Hygrade CV164:
6318,6319,6320,6321,6322,6324,6339,6340,6341,6342,6410,6411,6456,6457,6459, 6460,6461,6462,6463,6503,9008,9009,9010,9011.9012,9014,9015,9016,9023,9024, 9046,9049,9050,9051,9052,9053,9054,9056,9057,9058,9059,9062,9063,9064,9065, 9066,9068,9069,9072,9073,9074,9077,9078,9080,9081,9094,9095,9097,9099,9100, 9101,9102,9103,9108,9112,9114,9116,9119,9127,9140,9149,9153,9182,9188,9190, 9221,9243,9251,9252,9254,9275,9279,9281,9288,9292,9296,9359,9370,9375,9376, 9379

Carter 170-1409 (non-electric assist):

Carter 170-1490. Chrysler 4027792,4095984,3830548,4027714,4095341. Hygrade CV172,CV174:
6452,6453,6454,6455,6488,9002,9004,9055,9076,9093,9104,9115,9123,9124,9125, 9126,9134,9136,9137,9147,9152,9173,9183,9185,9187,9193,9194,9195,9196,9197, 9198,9202,9207,9208,9209,9210,9211,9215,9216,9217,9218,9223,9224,9225,9226, 9227,9228,9229,9245,9246,9250,9255,9256,9265,9266,9268,9269,9270,9271,9272, 9273,9276,9277,9278,9298,9299,9311,9314,9329,9330,9331,9332

Carter 170-1598 (non-electric assist):

Carter 170-1621. Chrysler 4095331. Hygrade CV241:

Carter 170-1675:

Carter 170P-1322A:
9800,9801,9810,9811 (integral choke, 9000 series)

Also note: 73-up without electric assist: Chrysler 4027795, Hygrade CV370.

Choke Pull-offs:

Note: Most of the TQs used the same choke pull-off. Many 81-84 units used the same diaphragm with a different bracket for the tamper-resistant housing. Some 81-84 Dodge trucks, IHC units and Ford used a secondary pull-off. The listed pull-offs cover most applications...

Carter 202-742, 202-664 (71-up)
Chrysler 3621210, 4049239, 4049240, 4049275, 4131250 (71-up)
Hygrade CPA77 (71-up)
IHC 460369C1 (74-80)
Ford D4AZ-9J549a (74)
KEM CP146 (71-up)

Carter 202-818 (81-84 tamper-resistant)
Chrysler 4267133 (81-84 tamper-resistant)
Hygrade CPA276 (81-84 tamper-resistant)
KEM CP319 (81-84 tamper-resistant)

Carter 202-821 (81-84 secondary pull-off)
Chrysler 4267137 (81-84 secondary pull-off)
Hygrade CPA269 (81-84 secondary pull-off)
KEM CP320 (81-84 secondary pull-off)

Carter 202-981 (84 secondary pull-off, vacuum controlled)

Miscellaneous Parts:

O-ring, main well cavity:
Carter 163-90, Chrysler 3685655 (or 3549406)
Needle & Seat:
Chrysler 3621161, Carter 25-1086 (OEM size), Hygrade VN87C
Accelerator pump:
Chrysler 4094867, Carter 64-465
Spreadbore/squarebore adaptor:
MP P4007522, Edelbrock # 2691.
Air horn gasket:
Chrysler 53030600
1/4" spacer base gasket:
Chrysler 3698365
Set of four, 1/4" spacer base gasket (3698365):
MP P4007902
Solenoid Bowl Vent:
Carter: 213-93 (78), 213-145 (79-84 Truck, 79-80 CA), 213-211 (81 CA MT, Can, 81-84 Export), 213-111 (80-84 Mexico), 213-229 (CA AT Truck), 213-240 (81 CA late Truck) Pulsing Solenoid (O2):
213-193 (81-84 318 car)


Air Valve Tool:
Carter 109P-397, Miller Special Tools # C-4152B

Strip Kits...

Carter produced Strip Kits in the 70s through the mid-80s for the Thermo- Quad. These are tuning kits for modifying the performance of the TQ. They consist of various metering rods, primary and secondary jets and needle/seats. There were kits for the Competition Series and specific kits for the early OEM/9000 TQs. Later, Carter consolidated the kits for the 72-later OEM and 9000 series into a single kit. Carter also offered kits for the WCFB, AFB, and AVS four barrels. A current version of the AFB kit is still available. All the TQ kits and others have been discontinued. Following is a listing of the early and late TQ kit contents. The other kits are also listed as a reference.

Early Kits, CS and other carbs:

Kit #Carb Type and Models Covered
10-101AFB 3783, 4758, 4759, 4761, 9500, 9625
10-102AFB 4760, 4762
10-103AFB 3361, 3720, 3721, 3804
10-104TQ CS4846S, CS4847S (press-in jets)
10-105TQ CS4846SA, CS4847SA (screw-in jets)
10-106AVS all
10-107AFB 4139, 4324, 4325, 4343, 4402, 4430, 4431, 4432, 4619, 4620, 4621, 4742, 4745, 4746, 4969, 4970, 4971
10-108WCFB 2669, 2816, 2817, 2818, 3059, 3060, 3061, 3190, 3191, 3500, 3501, 3696, 3697
10-109WCFB 2214, 2218, 2219, 2330, 2351, 2361, 2366, 2419, 2505, 2574, 2575, 2626, 2627, 2656, 2657, 2829, 2830, 3181, 3769

Early Kits, OEM and 9000 TQ:

Kit #Carb Type and Models Covered, with contents
10-110TQ 4972, 4973 ('71 340)
  • primaries: .074, .077, .080, .083
  • secondaries: .119, .122, .125, .128, .131
  • needle/seats: .0935", .111"
  • rods: 655, 682, 683
10-111TQ 6138, 6139, 9002, 9011
  • primaries: .092, .095, .098, .101, .104
  • secondaries: .131, .143, .149
  • needle/seats: .0935", .111"
  • rods: 1998, 1999
10-112TQ 6140, 6615, 9034
  • primaries: .092, .095, .098, .101, .104
  • secondaries: .131, .143, .149
  • needle/seats: .0935", .111"
  • rods: 2000, 2001
10-113TQ 6090
  • primaries: .092, .095, .098, .101, .104
  • secondaries: .131, .143, .149
  • needle/seats: .0935", .111"
  • rods: 1995, 2005
10-114TQ 6165, 6166, 9800
  • primaries: .092, .095, .098, .101, .104
  • secondaries: .131, .143, .149
  • needle/seats: .0935", .111"
  • rods: 1996, 1997
10-115TQ 6318, 6319, 6321, 6322, 6324, 6339, 3640, 6342, 6410, 6411, 6452, 6454, 6456, 6457, 6459, 6460, 6488, 6616, 9013, 9016, 9017, 9022, 9023, 9025
  • primaries: .092, .095, .098, .101, .104
  • secondaries: .131, .143, .149
  • needle/seats: .0935", .111"
  • rods: 2002, ??
10-116TQ 6320, 6341, 6453, 6455, 6461, 6496, 9004, 9008, 9009, 9012, 9014, 9015, 9024, 9046, 9049, 9050, 9051, 9052, 9053, 9054, 9063, 9072
  • primaries: .092, .095, .098, .101, .104
  • secondaries: .131, .143, .149
  • needle/seats: .0935", .111"
  • rods: 2003, 2004

Later Kits, OEM and 9000 TQ:

Kit #Carb Type and Models Covered, with contents
10-203TQ All 1972 and later solid fuel type carburetors.
  • primaries: .092, .095, .098, .100, .101, .104
  • secondaries: .131, .137, .143, .149
  • needle/seats: .0935", .111"
  • rods: 1996, 1997, 2002, 2003, 2004, 2005

Later Kits, AFB, AVS:

Kit #Carb Type and Models Covered
10-201AFB All 9000 series, all Competition Series, All OEM w/2 step rod.
10-202AVS All, All OEM AFB w/3 step rod, high step primary jet.
Note: Special thanks to David Wright on the MML for providing copies of the early documentation and typing the early kit contents and applications.