1964 300 HP 3721S Carb Problem

[M W.]

Hi all,

I have now just put everything back together with my 327 300HP engine after a complete cleanup and refurbish what was needed and my mechanic and I are at a cross roads with my carb. The car has all the original linkage but the secondary butterfly valve will not fully open. My mechanic estimated the car is losing around a 1/4 of it's total output. From our limited knowledge we have tried just about everything. Any help here would be greatly appreciated. If further details are needed please ask. I can also provide pictures if needed.

Thanks,

Craig

[Duke W.]

Re: 1964 300 HP 3721S Carb Problem

Are you talking about the secondary throttle valve or the "auxillary" air valve mounted above it.

Do you have the 1963 Corvette Shop manual and 1964 Supplement?

Duke

[M W.]

Re: 1964 300 HP 3721S Carb Problem

Duke, without speaking to my mechanic I think he is referencing the secondary throttle valve. When the pedal is mashed all the way down that valve is only opening about half way. I do have a 1963 Shop manual and I will definetly reference it tomorrow. Hopefully someone else here has experienced the same situation and can offer some simple advise.

Thanks,

Craig

[Duke W.]

Re: 1964 300 HP 3721S Carb Problem

The 1963 Corvette Shop Manual has a very detailed section on how to adjust all the various links and levers on the AFB, and the 1964 Supplement has any updated specs for '64. I recall specific detailed instructions on how to check the secondary throttle opening and adjust the linkage as required.

If you can change spark plugs, you can properly set up an AFB using the factory Service manual, a set of feeler gages, and a small machinist's scale.

There are no silver bullets - just read, comprehend, and do it by the book.

Duke