It may have been suggested already, but have you considered swapping a on a decent aluminum 4 barrel intake like a Edelbrock RPM or Weiand Stealth or Street Warrior and a new 4V carb like a Summit 500CFM? Nothing extravagant or too large…but at least they are new parts that won’t break the bank.
I think he did a compression and leak down test and those were good...IIRC. At the risk of being repetitive of myself, the first thing I would do is yank the distributor and have it rebuilt/recurved by Dan Nolan...regardless if it is new or previously rebuilt. I would also replace the intake manifold and carburetor with better options along with a new carb spacer and gaskets. I would be 100% shocked if it didn't run perfect after a proper tune was installed with these upgrades.
P.S. As a matter of fact, you order the parts, get the distributor rebuilt by Dan, bring the car and new parts to Huntsville, I'll help you do the work.
He sounds much closer than I. I would definitely try that route first. Don’t take it personal, but I’m not interested in driving three hours to do anything but race. All my tools are here. I’m comfortable working at my place. Honestly, if you would do as I have suggested, you can likely do it yourself and have a huge sense of accomplishment…especially considering all those that have failed you thus far.
Start with a fresh rebuilt distributor. Tune it properly. Then move to a KNOWN GOOD carburetor.