The axles will not interchange. to get the 9 1/4 rear with the 5x5.5 bolt pattern go to the salvage yard and find 4x4 dodge 86-93 with the 9 1/4 and pull the axles out and.

The drums from the 8 1/4 should work as long as they are the same size drum brakes if not chance the whole drum assembly out. drive shaft might not work?

Hope this helps.