Heh, the axle in my bus is already the modern upgrade! It originally came with the banjo shaped housing T150.
A new rear would mean new brakes, a new wheel bolt pattern, probably moving/welding spring shackles.
Since I'm lazy, and this axle was actually made into the late 1980s, I'm going to keep looking. There are 5.54:1 gears available, somewhat. Weller has a used ring and pinion set, it's $600, but that's a lot cheaper than the above mentioned new axle adaption hassle, especially since I just bought all brand new 22.5" wheels for it. @Mike B also yes, I'll be putting taller tires on it too. There's plenty of room in my wheel wells.
