[Grimpala]

I'm in the market for a 3/4 ton late model 4x4 with a duramax. I plan to do exactly what you're talking about. It shouldn't be too hard. If you can weld in a new crossmember and rear axle then it shouldn't be too much harder to fab new body mounts. Plus the newer frame is stronger and all the geometry is made to fit the frame, plus you benefit from 30 more years of engineering advancements in suspension, braking and ride quality.