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

I once had a problem with a mini-starter hitting the block but I never figured out what particular application that starter was for/from. I don't recall the year of the block either. It never happened again with several different OEM and aftermarket mini-starters. Like moparlvr166, I had to grind the block. It was around one of those open factory holes that lead up into the bellhousing area from the bottom at the back of the block. Tight fit with a grinder. I also ground on the starter. 360 LA block, later model 904 and TTI headers.