The swap to a later model frame will be a lot of work. I would convert the front end to ifs from a 3/4 ton, and that will be a lot of work, too. The frame on these trucks is narrower. For a differential, get a 14 bolt corporate from a late model gm. If you want to run duals, you will have to extend the fenders and/or tub the bed to make things fit. For an engine, either go with a diesel or a big block v8, otherwise you won't have enough torque. I understand the 4L80E tranny is a great od auto, but I think it requires a computer controller.
