Definately vacuum leak. But not where I thought it was. I bought a very inexpensive automotive stethoscope and attached an extra length of tubing to it, Then while the engine idled I went hunting for the whistle. It was loudest around the center intake port but then as I probed around I discovered it was ear splittingly loud at the carb baseplate area right below the floatbowl.
I have a 3/8" aluminum 4 hole spacer. The loudest whistle was at the carb and spacer plate interface. I used the very thin black paper gaskets that I have always used with success with the V things I have fiddled with in the past. I'm suspecting these gaskets.
I took the carb and spacer plate off and replaced both gaskets with new ones that I had in my spare holley parts box. The vacuum leak is still there, only worse, and is still at the spacer but in a different spot. Evidently the spacer, or manifold flange, or carb base is not flat and the black thin paper gasket is not doing the job.
Felpro makes a thicker gasket and I will get a couple of those to try. I will also check my spacer for flatness as well as the carb baseplate.
I will get this.
Youtube link
http://www.youtube.com/watch?v=i91fw1OA96o
