Hello:
Think your on the right path by looking for a mechanical problem, but my experience with Holley Carbs is somewhat limiited. I have always used Carter (now Edelrock Carbs much easier to tune, in my opinion.) I'm sure someone here can help you on the Holley.
Engines are complicated devices and nothing you can pour out of a can will cure a badly tuned or improperly built engine.
That comment is not a reflection on you or your talents, just something to keep in the back of your head.

Maynard