check the intake gasket ,the metal with valley pan built are good for warping and sucking air there might not be anything with your carb.
What was your idle speed with the Holley? And with the AVS did you try backing the timing down some?
I'm sure you tried this, but did you blow through the idle passages with compressed air, just to make sure there wasn't any junk holding something up?
Well, dogonit, anyway. That was a lot of time lost.
RIP AVS,SOB.
lol