Still didn't say what its doing.

Gm did use some different starters but some of them interchange. My dads mud buggy has a carbed 4.3 (don't get me started on him swapping FI to a crappy carb) and its running a starter off a 305 that was in my nova.

 

Do u know what trans he's running?or what flywheel?I need an inline bolt pattern.the other starters didn't come out far enough and sat to far away from the flywheel

 

You STILL have not said what it is doing.
Is it just spinning and not engaging the flywheel turning the engine over? what is it, or isnt it doing?