8.75 housing ends

340mopar said
The bigger bearing will carry more load. Being the OD of the bearing is bigger it means the ID is probably also bigger meaning a larger diameter axle. I guessing the later is the main reason for the bigger bearing.

See, I thought that too. But if you look at this page, it looks like Strange makes a bearing that is meant for a regular sized mopar axle shaft, but has a 3.150 OD for the bigger end. (Look at part # A1021 & A1022) Sounds like it would be a pretty stout set-up for someone wanting to keep their mopar brake set-up.