Weird 904 to 408 magnum starter interference issue. Dakota starter won't fit? 64 push button trans. is that the problem?

4eighteener said
Was that the standard mini-starter, or the short one that @slantsixdan recommend they eventually ended up using?

If you are asking me, that was a powermaster Mopar mini starter, which is a little bigger/longer than the standard mini, which I also have,and test fit before/after the block modification.