I knew that part number = hammer.
Trimmed the stock GM fork a touch, R&R'd the bell housing, and installed the GM ball with GM fork. Tons of clearance now no issue at all having the block plate. Just need to install a different boot and it's licked. I'll button up the engine tomorrow and start on the heater core right after that. Exhaust next week when this crappy mountain weather starts to smarten up.
An interesting note is that the GM Ball and the Lakewood Ball were identical lengths at 1.500 and the same ball width, but the GM # you gave me had a slightly broader (flat area) machined-face which really helped position and locks the GM fork much better than the Lakewood fork positioned itself. Never again would I ever try a Lakewood fork. Damn waste of time and resources. The allan bolts actually worked great except for one which was a pain and needed a shortened hand wrench to remove. I replaced that one when I reinstalled it before dinner. All good now.
Great clearance now but need to fit the boot better and glue it in. The stock fork made all the difference in the world.