Whistle in carburetor?

Question

when you start the car it whistles, when you step on the gas it whistles' the carburetor is a holly 2 barrel. its on a 318 dodge pickup.

Answer 1

Eminus or Aflat?  Could be a bit of carb gasket material sticking out into the phleum or the base gasket is slightly off kiltered on it.  Not a worry.   Put the air cleaner on, and the whistling will go away.  

    If the cleaner cover is on, then a vacuum hose is leaking(either cracked or pulled off)  Remove aircleaner , inspect and repair.

Answer 2

A vacuum leak sounds like the culprit.  Check the carburetor mounting studs and nuts for looseness.  Make sure they are all torqued evenly.  They should be snug, but not overly tight.  Also, spray some carb cleaner around the base of the carburetor.  If there is a vacuum leak,  the engines rpm's will drop slightly and the whistling noise may disappear briefly.