A833OD Questions

Straight 4 spd with 4.80 bearing retainer and overdrive both use a 308 front bearing in the transmission and both retainers share bolt patterns. That's why you can swap the 5.125 retainer for a 4.80. As stated above some have bored their bellhousing with the smaller bore out to 4.8. While it sure would save clutch linkage hassles, you might want to double check if the particular bell you're using has enough meat around the retainer bore before doing so.

A couple of years ago Mother Mopar (Mopar Performance) had a run of the various size bearing retainers made up. Making them available again drove the cost down of what was out there used, at least for a while.