Rochester carburetors can be identified in a number of ways--a metal tag that can be triangular or circular, hanging from or pressed into one part of the carburetor or another. Other Rochester carburetors can be identified by a roll stamp: numbers recessed into the body or barrel of the carburetor, rather than being raised above the surface like casting numbers. Some Rochester carburetors are indistinguishable from Carter carburetors except for the Carter four-digit part number, and parts can be interchanged.
Look for triangular aluminum or brass tags, roll stamps on the carburetor bowl or other identifying marks, like a round tag pressed into the side of the bowl. Note that Rochester carburetors cannot be identified by casting numbers alone. Triangular tags were attached to one of the screws which held the carburetor's air horn on the carburetor bowl.
Look for colored triangular tags or round tags. Between 1949 and 1956, the triangular tags were made of brass. In 1956, Rochester began using aluminum tags. The aluminum tags were colored on top, but the color may have disappeared due to the use of carburetor cleaner. Round tags were used from 1965 to 1967 on Quadrajet carburetors and the tag was placed into an indentation on the bowl behind the throttle arm.
Look for a roll stamp pressed into the bowl. In 1968, Rochester carburetors were "roll stamped." They each had identification numbers pressed (recessed, rather than raised) onto the side of the carburetor bowl.
Look for a Carter carburetor part number. Carter Carburetor Company Quadrajets were produced from 1966 through 1979. The markings are the same as Rochester and the parts could have been interchanged. Carter Quadrajets that are aftermarket replacements are identified by four numbers--a standard Carter part number, in other words--followed by the letter "S."
