Starter issues

[NHRA 303]

Since May I have been having a starter problem. When I hit the starter switch. The starter just grinds against the flywheel. This is a small block Chevrolet stick shift stocker. With everything removed. I can physically watch the starter gear grind against the flywheel face. Not the outer diameter of the ring gear.
My initial set up was a 142 tooth flywheel. With a 14 tooth GPE starter. It had plenty of clearance in the tip to root of the gear. GPE calls for .030. I have about .040. With the pinion when pulled into the flywheel gear it is engaged 50% of the ring thickness. (Optimal per instructions) With this set up it was grinding about 50% of the time. No matter how much I shimmed the starter down. Or spacered the motor away from the flywheel. GPE suggested trying a 9 tooth pinion. That was much better. With only occasional grinding. But then it progressively got worse.
So a good friend of mine let me borrow his 153 tooth flywheel clutch set up.(thinking that the 142 flywheel in the problem) With his starter. No grinding.
So I ordered the correct mounting plate for my GPE. Installed it. No problem. No grinding for roughly 40 starts. Then yesterday im loading my car into the trailer. And once again the grinding returns???? Worked fine all day. Then when the third round call came. It just kept grinding. I had to crank it about 20 degrees to a better spot. I was able to go one more round by popping the clutch while stopping.
So I know that its not the flywheel. And not the starter. Ive already had GPE go through it. Is it my engine block? If it is. Why hasn't it ground up till now. The bolts are tight when I remove it.
Any help here will be GREATLY appreciated guys. I have spoken with the clutch, and starter builders. And nobody can figure this out.



Thank you in advance. And sorry its so lengthy. Its been a long three months...

Steve Tucholsky
Cleveland,Ohio

D/S 1966 chevy 2