wrong starter or flywheel? won't turn over

[67mbsc]

I bought this 68 Chevy p/u with a 78 Camaro 350 engine, 3 speed manual, with the original bellhousing that bolts to the frame.
The previous owner told me the Starter went bad, and he replaced it with one that is for the bellhousing, 68Chevy p/u. It has the cast iron nose.
This is where the questions start. He said after that, the engine will not turn over. So, I bought it like this, with no old starter, just what looks like, inside and out, like new. I took out the starter, checked everything, even the fields, and brushes, all IS new. The teeth of the starter drive appear to show where the teeth of the flywheel are reaching all the way into the teeth, even touching. I’ve compared other new drives, all the same dimensions. The outer edge of the flywheel is very close to one edge of the bellhousing, but not touching.
Please keep in mind, this was running fine before the starter went out, so physically, this setup should be operable. When I turn over the starter with the key, or jumping the solenoid direct, the starter will groan, sometimes go very slow, or not at all. It’s acting like it needs shimmed, but the cast nose prohibits shimming.
I took the starter to a shop, they tested it, it’s fine.
Please help if you can, I’m stumped! I can turn over the engine with a 3/8 ratchet, it’s not stuck

[cdowns]

you should maybe read up on the board rules about double posting