Sand dollar:
Rochester is a carburetor manufacturer. They produced carburetors as original equipment for Chevrolet beginning in 1950. The model or type of carburetor is a model B. If the carburetor had an automatic choke, it was then called a model BC. Many different variations were produced, and these are identified by a 7 digit number, originally stamped on a triangular tag, thus called "tag numbers". Many of the tags are now missing, and identification is very difficult to sometimes impossible.
Carter is also a carburetor manufacturer. Carter produced carburetors as original equipment for Chevrolet from 1923 through 1949. Beginning in 1950, Carter produced AFTERMARKET carburetors for use on Chevrolet engines. The model or type of these carburetors is a model YF. There are a number of variations, and these are identified by either a 3 or 4 digit number followed by the letter "S" as in (S)am. Carter knew the tags were going to be thrown away, so most (not all) of the Carter model YF carburetors have the identification number STAMPED (a recessed number produced with metal marking stamps) on the center section of the carburetor.
Here is a link to the various Carter YF carburetors produced for use on Chevrolet engines:
Carter YF's for ChevroletIf this doesn't clear up the confusion, give me a call during normal telephone hours (9-12, 1-4 Mon-Tues central time) at 573-392-7378.
Jon.
