Rochester Quadrajet carburetors up to and including the 1967 model year were identified by a round, pressed-in aluminum 'bottle cap' tag on the driver's side of the float bowl near the front.
Starting in 1968, the number was stamped on the driver's side of the float bowl above the secondary throttle shaft.
Rochester-built Quadrajets have numbers starting with '70' or '170'. Carter built carbs have a 4 digit number. Quadrajets used by other manufacturers were sometimes assigned their own number, which appeared on a tag screwed to the front of the airhorn.
click on a link below for kits and other parts listed by carburetor number
Rochester Quadrajet (Complete list)