I am installing an engine from a 1996 Chevy truck into my 1982 Z28. The question I have is; the starter will not properly line up, or so it seems. When I first cranked it, the flex plate was not bolted to the converter and the starter made a terrible sound, screeching and so on. I was like no problem, so I went under the car and eventually used all of the traditional SBC shims I had on hand on my offset new REMY #96206 to no avail. So I went to the auto part store and bought even more but this time I used the correct offset style. I installed them along with a modified shim from the first batch. Then I re-cranked it, same noise. Then I went under the car (working by myself) and noticed that the starter Bendix was still engaged in the flexplate!
Do I need to add more shims, and keep at it?

 

Trucks use 168-tooth, 14" diameter flex plates. 3rd gens use 153-tooth, 12-3/4" flex plates.

I assume you're using the 3rd gen starter with the truck flex plate. It won't work, no matter how many shims you use.

Either use an '86-up 3rd gen flex plate, or a truck starter. You can't mix starter and flex plate types.