Which Tremec are you using?
I run a T56 Magnum with my Gen 3 with TTI 1-3/4 headers and any parts store Mopar mini starter should work. The starter needs to have the spacer for one of the bolts or else the hole will be too big and will be loose when cranking the engine. When that happens the ring gear teeth will be chipped off and the engine will not start. You then have to use a torch to be able to flip the ring gear on the flywheel over.

Yes I had to trim the bosses as well. I ran everything with uncoated headers when I got my engine dyno tuned and then pulled them off to get them coated locally. They are a pain to pull off but can be put back as long as you get the angle correct. This is with a stock style k frame as well.