Hello


I am running a slant six with an Offenhauser intake Dutra duals set up and a Holley 390 carb. Whenever the car gets up to operating temperature the carburetor starts to whistle. I installed a Mr Gasket heat shield and a phenolic carb spacer but the problem (although reduced) still exists. I thought that it might be a vacuum leak but when I cool the carb with carb cleaner then the whistling stops. Could there be something that partially plugs and causes this sound or perhaps some sort of seal that is heat sensitive and starts to leak at 180F?