Backin Plates...

7.25 bearing is smaller in diameter than 8.25 or 8.75.

7.25 backing plate center hole is too small
Nope, not by much AT ALL. In fact, I could almost clean the dirt and rust out of the center hole and the 8 3/4 housing end would just about fit. It won't take much with a dremel AT ALL. In fact, I'd bet I could pull it in just by tightening the nuts down. It's THAT close. I damn near pushed it all the way in by hand.