The key thing on Holley type carbs is that the throttle blades need to be set at idle so that only a small portion of the transition slot is showing. Do not move the throttle blades once the position is correct! Changing the idle speed with the idle adjust screw is only okay for very minor adjustments.

If the engine needs more air at idle than it can get with the throttle blades in the correct location then you have to get the air from somewhere else. The newest carbs have idle air bypass the older carbs used holes drilled in the throttle blades.

The new Dominators use air bleeds in the top of the carb body that go directly to the intake manifold so you can change jet size to adjust the idle air bypass.