Holley whistle!

Ok, so I have a 650 DP 4777-3 holley that workes great, but I wanted bigger so I bought a 4779 body, transfered everything over from the 650 to the 750. It runs great; however, it whistles loudly at idle between 500-900 rpm. I checked several times for a vacuum leak and I do not at all. I used carb cleaner, propane and covered the air horn. Absolutely positive no leak at all. I really think it is coming from the throttle blades on the primary side.
I was thinking that, if I could to either open or close the secondary blades some, the angle of the primaries will be different to keep it from whistling. It whistles so loud, with the aircleaner on and hood closed, you can still hear it from 20 feet away.
Any suggestions?