Rochester whistle?

I ran across this years ago, a friend was having a problem with his carb whistling, and I can't remember the cause. Now another friend has come to me with the same problem and is looking to swap out the original carb/intake for what I remember to be a simple cure. I think it was in the acc pump. Does this sound right? Been too long since I fixed the last one. this guy hasn't even started his car in 2 years because of this.

Devin