I am looking at the same thing this week. I have almost decided on the Ford 11000-A50 unit.
It appear the fit up shakes out this way.
The most common starters fit all 157 tooth flywheels and flexplates, and 164 tooth auto flexplates. The 164 tooth flywheels seem to take a starter with a different nose piece. I confirmed this a few years ago looking a the stick and auto replacement starters on the counter at Carquest.
Which one are you looking at?