[HOGOAT]

Have Carter Quadrajet with number on back 7037576. Also has number in a semi-circle on top 7037535., and number on side by throttle 48529. Does any one know what this carb is off of. I would like to use it on my 70 GTO with a 455HO.

 

[lars]

The carb number is in one of two locations:

It's either right above the secondary throttle shaft on the driver's side, stamped vertically into the body of the carb, or (on a Carter-manufactured Q-Jet) it is in a round seal under the accel pump linkage above the primary throttle shaft on the driver's side. The numbers on the back of the carb and on the top of the carb are casting numbers, and do not denote the carb. If you post the correct number I can tell you exactly what you have and how it should be set up.

 

[HOGOAT]

Carb #

The only number stamped into the carb is located vertically on the drivers side by the throttle linkage it is 4852S and below it is L2. The S could also be a 9. It's hard to tell.

 

[lars]

Those numbers are the date codes. Normally, the carb number is stamped right by that date code. Is there is small round "seal" cast into the carb on the driver's side of the float bowl right under the area where the accelerator pump rod goes by the casting? If the carb is a Carter-built Q-Jet, the carb number was often located on a foil tag that was pressed into a round seal at this location. If it's a Rochester Q-Jet, the carb number was always stamped by the date code that you found.

I checked both the 7037576 and the 7037535 numbers. Neither of these numbers are valid Q-Jet carb numbers from either Rochester or Carter.

Any Q-Jet can be successfully used on a 455 GTO, but it really helps to have the correct carb number so you can check and set up the correct jetting for the carb as a tuning baseline. Pontiac Q-Jets have the fuel line inlet going straight into the front of the carb, whereas Chevy had the fuel line coming in from the passenger side on the front of the carb. However, other GM Divisions also used the straight-in fuel line, so the front-facing fuel inlet does not positively identify the carb as a Pontiac.

If you can post or e-mail me some photos of the carb, I may be able to identify the year and Division for you if there are no numbers on it. But a Q-Jet without a carb number would be very unusual...