Picked up a 833
Its a 23 spline and cant really get a good measure on the retainer it around 5in.
There are 3 Mopar bearing retainer sizes.
5.125" = 75 and later overdrive
4.80" = 18 spline Hemi trans
4.35" = Everything else
A buddy of mine just picked up the same trans as yours,so I just went through all of this. His trans had the same exact shift bracket as yours. The trans was out of a 75 truck. You have a OD (overdrive) a833 trans out of a 75 and later truck. All I am going to say,is Huge Can of Worms.After talking with me,this trans is for sale.
By the way,
What is wrong with a nice 904 with a shift kit behind your small block ?
Not trying to talk you out of anything.Doesnt really matter to me what you use.Just speaking from experience her.Put a nicely built 904 back in, and $ wise, you will be way ahead of the game.