Hello

I have a Holley 390 that I have been running on a 225 slant six with an Offenhauser manifold.
There is a persistent vacuum leak that seems to come from the gasket between the manifold and the carburetor.
When ever I change the gasket the leak stops for about an hour and then starts again.

This leak is on the inside edge of the gasket and causes a very loud whistle sound. If I spray some carburetor cleaner in the mouth the the carb the whistle will stop for a while then come back.

I am wondering, would a rebuild stop this?

Could this leak be due to something being warped?

Am I just using the wrong type of gasket?

Thanks

Are you sure it is not between the carb mounting plate and manifold? I have had the plates leak and do the same thing.

I always seal the plate straight to the manifold with silicone.

What type of carb mounting gasket are you using? I have always used the gray paper ones and not had any problems, even when I re-use them 10 times.

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Official Cookie and Mater Tormentor.

Hi

Thanks, I think that the problem is that since I put a so called "dropped bottom" air cleaner on that too much heat is being trapped and that the gasoline is actually boiling!!!

The the whistling sound. I am going to try to put on an insulating gasket and a regular air cleaner.

The noise could even just be the throttle plates. When it is making the noise can you spray carb cleaner at the base & detect the leak. Or is it just noise.


jess

Hey

I tried my idea of using the non dropped bottom air cleaner and that did the trick.

I also put on some special insulating gasket from Mr. Gasket and that may have helped as well.