carburettor power valve

[Jack Steele]

I have a blown power valve in the primary side of my correct Holley carb. The documents that come with a carb parts kit states and supplies # 8 to 4.5 depending on the carb part number. My Holley book says to us a power valve 1.5 numbers less then the idle vacume which is 13.5 on my 396 engine. Even Napa only supplies 6 or 4.5 power valves. which is correct.

TIA.

Jack Steele
1965 Corvette. 396 engine.

[Michael B.]

Re: carburettor power valve

From the Holley website....

QUESTION How do I tell what size power valve I need?

ANSWER To properly size a power valve, take a vaccum reading at idle and if it is above 12" for a standard transmission a 6.5" will be safe to use. For automatic transmissions take a vaccume reading in gear at idle and if the vaccum is below 12" divide that in half for proper size. Example 9" of vaccume in gear at idle will require a 4.5" power valve.

[Michael B.]

Re: carburettor power valve

From the Holley website....

QUESTION How do I tell what size power valve I need?

ANSWER To properly size a power valve, take a vaccum reading at idle and if it is above 12" for a standard transmission a 6.5" will be safe to use. For automatic transmissions take a vaccume reading in gear at idle and if the vaccum is below 12" divide that in half for proper size. Example 9" of vaccume in gear at idle will require a 4.5" power valve.

[Ken A.]

Re: carburettor power valve

All big blocks use a 65 power valve. You should also install the anti bolw out kit while you're at it.

[Ken A.]

Re: carburettor power valve

All big blocks use a 65 power valve. You should also install the anti bolw out kit while you're at it.

[John H.]

Re: carburettor power valve

Jack -

There's no listing in the '65 Shop Manual Supplement that details the LIST 3124 Holley on your engine due to its mid-season introduction, but the carburetor numerical listing chart at the Holley site shows the 3124 as originally using a #85 power valve.




Holley Carb Numerical Listing

[John H.]

Re: carburettor power valve

Jack -

There's no listing in the '65 Shop Manual Supplement that details the LIST 3124 Holley on your engine due to its mid-season introduction, but the carburetor numerical listing chart at the Holley site shows the 3124 as originally using a #85 power valve.




Holley Carb Numerical Listing

[Jack Steele]

Re: carburettor power valve

Thanks guys. I knew that someone would know.

Thanks again

Jack