Edelbrock 1460 Carb 1st Test Flight Noise??

It is possible to get the 'whistle' from:

1)worn throttle shaft bore; the bore in the base plate will elongate the amount of degrees that the throttle lever travels from an idle position to wide open throttle position,

2) the base gasket; this carb base to intake gasket can cause a whistle when gas saturates it and the vacuum in the intake causes the saturated gasket to distort temporarily. Also the style of base gasket can also cause the whistle. For example, if your base gasket is a four hole and it does not match the mounting surface of the intake, it will happen. Stacking multiple base gaskets may be causing this,
3)and badly worn or damaged primary boosters also.

With the loud sound at an idle, I would suspect the base gasket as being the problem, David.