Carburetor Identification
AA Series – (1949, 1950) (2 barrel) triangular metal tag
B Series (B, BC, BV) – (1949 - 1967) (1 barrel) triangular metal tag
2G Series (2G, 2GC, 2GV) – (1955 - 1967) (2 barrel) triangular metal tag
2G Series (2G, 2GC, 2GV) – (1968 – up) (2 barrel) roll stamp on side of bowl
4G Series (4G, 4GC) – (1952 – 1967) (4 barrel) triangular metal tag
H Series (H, HV) – (1960 – 1967) (1 barrel) triangular metal tag
H Series (H, HV) - (1968, 1969) (1 barrel) roll stamp on side of bowl
Monojet – (1968 - up) (1 barrel) roll stamp on side of bowl
Quadrajet – (1965 - 1967) (4 barrel) round metal tag pressed into side of bowl
Quadrajet – (1968 – up) (4 barrel) vertical roll stamp on side of bowl
R Series – (R, RC) – (1962, 1963) (1 barrel) triangular metal tag
Tags: Tags beginning in 1949 were brass. The metal was changed to aluminum approximately 1956. There appears to be some time overlap in the different series. The aluminum tags were color anodized on the top side. The color used was a code to help identify the carburetors. A few times in carburetor cleaner, and the color disappeared to a natural aluminum finish. The triangular tags were located under one of the screws holding the air horn to the bowl. The round tags (1965 – 1967 quadrajets) were pressed into an indent in the side of the bowl directly behind the primary throttle arm.
Roll stamps: Beginning in 1968, all Rochester carburetors were "roll stamped" with the identification number on the side of the bowl. These are "stamped" or "recessed" numbers, not "raised" as discussed below.
Other identification numbers: A very few 4G Series carburetors in 1957 only were stamped with the last 4 digits of the identification number on top of the air horn.
Casting (raised) numbers: Raised numbers appearing on various castings are so-called "casting" numbers. These numbers were used by Rochester to identify a casting "blank" PRIOR to machining. A casting could be machined into different parts. As an example; consider the throttle body of the 1957 Pontiac tripower: the front carburetor has no idle screws in front, and an 1/8 inch pipe tap in the rear; the center carburetor has idle screws in front, and an 1/8 inch pipe tap in the rear; the rear carburetor has neither idle screws nor pipe tap. ALL have the same casting number. IT IS IMPOSSIBLE TO IDENTIFY ROCHESTER CARBURETORS FROM CASTING NUMBERS ALONE!
Carter built quadrajets: Carter Carburetor Company of St. Louis produced millions of quadrajets under license from GM from 1966 through 1979. These carburetors carry the exact same identification as their Rochester counterparts, and parts are directly interchangeable. Carter also produced "aftermarket" replacement quadrajets, which will be identified by the traditional Carter part number (4 digits, followed by the letter "S"). An example of this numbering system would be 4675S, which is identical except for the number to 7028262.
Rochester part numbers and application: Virtually all Rochester carburetor numbers produced from 1949 through 1974 are included in the application listings on this website.