Thanks. I do understand the basics, (engine, trans, transfer case, exhaust, fuel systems, radiator), the things I was looking for are engine mounts, electronics, (how easy is it to plug into the oem wiring, as the truck did have the diesel as an option), changing the rear to a 3.73, will my Allison work as is with a Duramax, (or does it need to be reworked or even is the same model), etc. Removing an engine/trans and reinstalling is OK, but fabricating new parts and mounts takes a little more than I want to get involved with. Also I am seeking general advice as to costs, (beyond the engine/trans), the small pieces are really add up. I would think, and I am looking for verification, that swapping in a 3500 would be much easier than stuffing a Duramax into a Tahoe or Suburban. Lastly, what about inspections? How much trouble will one get into with their DMV? I spoke to one retailer of Duramax engines, they would not even sell me an engine as the truck did not come with one.