Steve,
Having a known "good" carb to put on and try is absolutely the best bit of diagnosis you can employ. That should go a long way toward pinpointing whether your problem is purely carb related or not.
Again, good luck and let me know the results.
Mike
BTW, don't be intimidated by Holley carbs, they're rather simplistic in their design and easy to work on. Only a few things to watch out for like the seal washers and check balls associated with the nozzles and things of that nature.