Hey Truck,
I went the other direction. I kept the torque tube housing in my 46-n-1/2 and put a "new" punkin in it (55 truck 3:90). Steppenwood has some great shots of his mod and I have a full set on my photo link as well.
With this option you can keep original axles so wheel offsets pose no problems and I too am running 235/85/16's.
Might be able to find someone giving away an old torque tube; see them from time to time on in the swap meet.
Cavebull
Cavebull