If your engine is too rich, then you should be belching black smoke out the ex. pipes when it "bogs"/lays down.
All carbs are pretty much alike, except Holleys have fewer jet adjustments than bike carbs or Webers. (The jets are there, they're just fixed.)
I suggest you go back to a stock main jet and start from there. Only go up a jet size at a time, just as you would with a race car carb. Be sure to keep notes on what you've done, too.
NOTE: If your spark plugs are fuel fouled because of too-rich a mixture, either clean them well or install a fresh set.
