Thank you very much. I have had the flywheel off while heating it up for that very reason. A manual impact is about the only thing I haven’t tried. I have one, but the biggest bit I have is a 3/8” and these screws are 3/4 across. Think that would tear it up? I already put a 3/8” slotted bit in my pneumatic impact and it just broke the bit right off.
I already have that parts manual and I did use the old school cotton plug wires. This ain’t my first rodeo, haha. When working on such an old machine a manual is usually my first move.

I will try to find or make a 3/4” slotted bit for my impact. If not, are the screws available?