I did a 283, TH 350 in my 1946 1/2 ton some time ago. For the rear end I installed the "Pumpkin" from a 1956 1/2 ton with 3:38 RATIO. The pumpkin bolts right in to the 46 housing. You will also need to install new axel mounts and weld them solid. the rear end has held up fine behind the built up 283. I can provide pictures if you need them.

Rick :^)