i have a 383 with a street avenger carb(brand new). and there is this horrible whining coming from it. it almost sounds like a supercharger whining. its constantly is making the sound from when i start the motor. all my vacuums are hooked up or plugged. its terrible everyone and their mom can hear it. its that loud.
any help?

Sounds like the carb is not seated on manifold, or gasket has a leak. Had the same sound when I added a spacer, and did not seat the carb flush. 8)

If no vacuum leak are found:
This may be air whistling around the primary throttle plates. Try changing the idle up or down and see if it quits. If so you can drill some small holes in the idle plate which will allow you to close them further or you may be able to get away with opening the secondary plates just slightly so you can close the primaries enough to stop the noise.
Mike.