5.3 or 6.0 into a 82 GMC 4x4

[mlevario99]

I am going to be doing a engine swap, the 82 4x4 GMC has the 6.2 right now, my friend wants a 5.3 or 6.0. He wants to swap just the engine, keep the original tranny. Question, what kind of tranny do this trucks come with, it is a automatic tranny. How dificult will it be, I did a swapa 4.8 vortec in a 76 ford truck, so I have some experience with these engines. Any advise, any threads that I can follow up.

Thanks for your help