Holley secondaries won't open
A thought that comes to mind is that you are trying to run thru a 4bbl to 2bbl adapter; I can under stand budget, this is what you've got, etc. It could be a portion of your pain.
I've run a Holley 3310 on a 318 in the past with good success, it takes patience. You haven't mentioned what spring you are using, there are 6 different possibilities, they go:
white the lightest
yellow
purple
plain (kinda silver)
brown
black the heaviest
This is one list I have; another list goes like this:
Yellow (short spring) Lightest
Yellow
Purple
Plain (standard spring)
Brown
Black Heaviest
A lighter spring will open the secondaries sooner; open too soon and it's a major bog, go to the next heaver spring. The secondaries should not open late with sudden surge like some one fliped a switch. When you get it right, you almost can't tell the secondaries have opened, it's a smooth steady pull with you right foot to the floor.
Make sure the diaphram isn't torn, the secondaries will never open if it is.