I can not find the original starter. The new min torque does not even come close to the flywheel when activated and a new conventional starter seems to engage partly. I have tried different shims and no shims to no avail.

Do you have the original flywheel still on the car, or has it been changed?
I thought that most of the mini-starters could be oriented to fit different flywheel diameters...?

and...do you happen to know the diameter, and tooth count of the flywheel you have on there now? Chances are all you need is a different nose for the standard type starter...Adams' Apple2008-11-04 11:18:10

I don't know about the flywheel, Still checking with the local Auto Z-blows.

I replaced the starter in the 80 vette with AC DELCO reman # 19136133 or 336-1824 depending on the store's listing this starter worked fine, stock flywheel/ring gear

  My 1980 has the 153 Tooth Flywheel and or Flexplate and in the last 20nYears or so I have had Two Auto's and four Flywheels. I'm useing the GM performace Parts Mini Starter sold in the late 80's and it has worked for everything so far.  I doubt You have the 168 Tooth Flywheel. With the Starter removed You can Mark a Tooth and turn the engine wile counting the teeth and figure out what you have. I'd say something else is wrong.

Any luck?