Brad - It sounds like the main jet threads are stripped. See top post. Not much depth for a helicoil or insert. Suppose it might be worth a try.
What's wrong with the speedmaster/procomp blocks?
I suspect one thing Brad's looking at is the emulsion and idle feed restriction. Easiest and most straightforward tuning will be setup like an old school Holley. This keeps the fuel most consistant.
You can make the blocks you purchased similar to the original blocks.
Some useful references and explanations here:
https://www.tapatalk.com/groups/racingfuelsystems/stickies-f31/in particular the ones titled
Relocating the Holley Idle Jet
Emulsion Tuning
Numerical Listing
