833 Front bearing retainer

I second calling Brewers. I don’t think you’ll find an off the shelf adapter. Will probably need a retainer that matches the bolt pattern, and is a larger diameter. Something like this (call Brewers though):

Brewer's Performance - Mopar A833 4-Speed Transmission and Component Specialists

Actually that should be exactly what he needs. I didn’t realize there was a 5.125” OD retainer with the 3.7” bolt pattern. Iron case overdrive maybe?