I need some engine installation help...

[LS1_C10]

Ok so this may ramble for a while, but it is a legitimate concern for me.
I really want a vehicle with a VORTEC 5.7L 350.
Ive had two, and I want another.
Im fairly sure they were only in 96-99 Chevys and GMCs.
I can pick up bad-motored 90-95s all day around here for dirt cheap.
I can get a Vortec crate motor for cost thru work.
Will there be any compatibility issues? Wiring harness, engine mounts, transmission, all that crap? I cant do this alone, so it'd be a shop doing it, I just need to know what all would need to be done.
I know they are all pretty much the same, but this could concievably include tahoes and burbs.
Has anyone done this?
Also...if I said screw it and bought a 99-05 Silverado....same question. The 5.3L is a joke. Could that be done?
I know I dont come around much anymore, but that'd change if yall helped me get another Silverado! Feel free to move this thread if you deem necessary.