So I had a chance to play around with it some on Saturday.
First I swapped over the vac advance line to manifold vacuum. It seemed a bit better but not a big difference there.
I think the real problem was the idle air screws were at vastly different settings. I played around with them a bit and got the engine to smooth out at idle. That seems to have made the biggest difference. It still wants to stall sometimes but not nearly as much.
I'll go back and re-set them with a vacuum gauge. I think that was the problem all along.
See:
https://www.holley.com/support/resources/specifically,
click on: "A Look Inside Your Carburetor"
scroll to "Idle System"
Might be of help. Might be good to read the whole thing.
I've had to tweak base timing while doing this before so keep timing light handy.
