Holley stumble trouble

Mattax said
But the important thing is that the idle changes when you adjust them.
Reduce the throttle position, and readjust the mixture for strongest rpm in gear. Or go leaner until the rpm just begins to drop, then turn 1/4 back richer.

Yes, the screws do affect the idle. I set them using a vacuum gauge to achieve highest reading in neutral (4 speed).

Mattax said
Is that 22* with or without the vacuum advance hose plugged?

22* idle timing is with hose disconnected and plugged.
I will map timing curve and report back.