whistle

every time my truck gets warmed up i hear this whistle noise i replaced my intake manifold it was cracked put new one on still got the whistle going on replaced gaskets on my weber carb but its still there idk if its my gasket on my headers cuz it dosent sound like the noise it made when the header gasket went bad but i replaced that with one of them heavy duty ones idk im stumped oh yea it only makes the noise when im on the gas..

does it change pitch with rpms or speed?

seems like it dose with rpm im kinda thinkin its my weber it made this sound before but its jus makin it when im getin on the gas then when i let off it gose away

Is the stereo on or off when you hear it?

I know that with the Weber I can hear it sucking in air when I mash the pedal, unlike the stock carb. This is the only carb vehicle I've ever had, so it was something I wasn't used to. I thought I had a massive vacuum leak until I realized it was simply the carb sucking air.

got no stereo in lol i was thinkin it was jus the carb suckin in air but it dose sound like a air leak but i sprayed it all down to see where it was comin from but no luck

Did you sand the weber adapter plates smooth? I've heard, mine were too, they are not always flat

Stick your hand over the carb and see if you get any more direction of where it's coming from.
Just be careful of backfires, though I've never had one.
If the engine speeds up you may have a leak, or it may be lean.
Old school

I should have also mentioned to squirt carb cleaner at the base of the carb/adapter plates while it's running. If the idle speed changes you have a vacuum leak.