You can usually find the carbs casting number and date code on the driverside of the carb stamped vertically.
A typical stamping;
70 = Rochester products division#
45 = Production year, 4=1970's, 5=specific year, 1975
2 = Carb ID, 2=49 state Q-jet
1 = Division, 1=Chevrolet products
3 = Tranny ID*, Even number=Automatic, Odd number=manual
101 5 = Julian Date Code, Friday April 11 1975
YA = Engine assembly plant
# Carbs starting with 70xxxxx are pre-1976. Carbs starting with 170xxxxx are 1976 onwards.
An important note: Primary metering rods are different lengths for the two units, both rods are available from GM, and the new-part part numbers correspond with the carb. Rods whose p/n starts with a 7xyz are for the 70xxxxx carbs, and p/n 17xyz are for the 170xxxxx carbs.
* tranny ID is not cast in stone. This particular example was original equipment on an automatic equipped pickup truck.
How about another? 17083222
Date Code 0183
Is a 1983 model year, 49 state Q-jet, Chevrolet division with an automatic tranny.
Manufactured on the 18th day of the year, in a year ending in 3. For, January 18 1983
Originally installed on a 1983 1/2 ton Chevy Pickup with a 305 and automatic tranny.
And one more for fun, 7043114
A 1973, 49 state 2bbl , Chevrolet division, with an automatic tranny.
Originally installed on a 1973 Nova w/350 and automatic tranny.
Remember to employ all safety precautions when working on any vehicle.
This information is only intended as an overview and may not include all the necessary information, data, or facts to complete the swap.
Remember, every vehicle is unique, and research for your particular vehicle is recomended.
This Page Created By Alexander M. Bilan (email@example.com)
All Rights Reserved
March 28, 1997
Revision 2.1 September 30, 2001