1997 Suburban Engine UPGRADE

I was wandering if anyone could tell me what direction to start looking in. I have a 1997 K1500 Suburban 5.7 ltr 4x4. I think that it has a 4l60E trans. She has over 100k on her and I wanted to swap out the engine for a more powerful one that would work with this trans. I would like to use something like the LS6 Escalade motor or one of the new 6.0 engines. Can this be done without a nightmare? It just seems to me that the new engines have all the more horsepower and get about the same MPG as my old pig. Thanks!!
Ken