204 East 15th Street
Eldon, Missouri 65026
The primary method of identification of the Rochester 4G series is a trianular tag. The early 4G tags were brass. The metal was changed to aluminum sometime during late 1956~early 1957. The brass tags were brass colored. The aluminum tags had an anodized color on the top side. The color was used internally by Rochester plant employees to help in the identification of the carburetor.
A secondary method of identification, but not present on all 4G series carburetors, is a stamp on the airhorn. This stamp was the last 4 or 5 digits of the tag number.
Note in the picture below (carburetor 7007221) the presence of the tag, and in approximate of the center of the picture, the stamped number 7221.
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!
Rochester part numbers and application: Virtually all Rochester carburetor† numbers produced from 1949 through 1974 are included in the application listings on this website.
We offer a carburetor identification service. If the carburetor can be readily identified (tag, or stamped identification number) there is a $10. charge per carburetor.
Some carburetors can be identified by casting number (most cannot). Again, this would result in a $10. per carburetor charge.
Many older (especially brass) carburetors can be identified easily only into a group of applications (example: a Zenith O-4). These carburetors have different internal venturi, different calibrations, and different throttle and choke hook-ups. Absolute identification, while possible, normally would exceed the value of the carburetor! There is a $20. charge for a print-out of the various applications for a carburetor such as this.
Some carburetors in this group are worth the absolute identification. An example of this would be the Stromberg EE-3. These were used on Duesenbergs, Chrysler Imperials, Pierce-Arrows, Delahayes, Deloges, etc. To positively identify one of these, we generally need to inspect the carburetor in person. Cost will vary with the amount of time necessary. Occasionally, one of these can be done via telephone (we would tell you what to look for). An example of this is the Duesenberg EE-3 is the only one to use 1 3/8 venturi. This number is cast on the outside of the bowl.
Many carburetors are simply not worth the time to positively identify. Examples of these would be Rochester 1 barrel units used on primarily Chevrolet 6 cylinders of the 1950ís and 1960ís. These were identified by a tag. Once the tag is removed, identification is extremely difficult.
If you wish carburetors identified, the best method is to send us a list by manufacturer, type, and identification number (if present). We can then tell you what we can identify, and the costs. DO NOT SEND PICTURES! WE WILL NOT ATTEMPT TO IDENTIFY CARBURETORS BY PICTURES!!!