Rochester Carburetor Number Decoding

Did you ever wonder what in the hell the numbers on your carburetor meant? when it comes to Rochester carburetors, In this day and age it is damn near impossible to take a carburetor into your local part’s store and find a clerk that can even recognize a carburetor let alone try and find you a rebuild kit! so in a nutshell you need to know what your carb came from to begin with so you have an idea not only to determine what carburetor kit to get ,but what it may have been calibrated for. Remember when chosing a carb…yeah you can always drill/swap out some jets but with these older rochesters, the passages-air bleeds-main jet-cfm rating-etc are hard set for certain size engines.SO, unless you know for a fact where the carb came from always check the number to see what you are dealing with.

Example: # 7028219
DG 1938

On most Rochesters you can find these numbers covered in shit on the main body. on the q-jets it can be found near the rear corner face of the main body secondaries going up the side of it. on a 2G carb it is on the side of the float bowl. you can sometimes be lucky enough to get one with a tag on it still but that is somewhat rare…..and the numbers are usually covered in corrosion and shit and by mistake-you scrub the numbers off trying to read them. rebuilders may or may not tag the core after the build.



Prefix code. “70” will appear on all late ’60’s Rochester Carburetors.
76 and later will start with “170”
2 – Decade produced.
702 – 1960’s
703 – 1060’s with A.I.R.
704 – 1970-1975
1705 – 1976-1979
1708 – 1980’s


Year produced.
8 = 1968
If the number was 7045219 then
5 = 1975
7028219 Model
0 – Monojet (1 bbl) Federal standards
1 – Two jet (2 bbl) Federal standards
2 – Quadrajet (4 bbl) Federal standards
3 – Monojet (1 bbl) California standards
4 – Two jet (2 bbl) California standards
5 – Quadrajet (4 bbl) California standards
6 – VariJet (2 bbl) Fed
7028219 – Division.
0, 1, and 2 all indicate Chevrolet.
4 – Buick
5 – Olds
6,7 – Pontiac
7028219 – Transmission most cases
Even numbers – Automatic Transmission
Odd numbers – Manual Transmission
DG Production Code.
1938 Rochester produced carburetor Date Code
193 = 193 rd Day of the year
1938 8 = Year 1968
A8 o MM Carter Produced carburetor Date Codes
A= Jan
B= Feb
C= March
A8 o MM 8 = year 1968
MM Production Code.

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