Technical 9 inch rear flanges

Looking at 9 inch rear ends, this one has an unusual flange on the front of it. Could you run a normal 9inch style drive flange on it instead of that one? Or can you still find a driveshaft flange like that still?

 

By the looks of it that just takes a late model flange that is held on with four bolts

 

Or you can buy a new flange to fit a normal U joint. You get into the pinion bearing preload when you do that, so read up on it first.

Might be easier to find the matching driveshaft...