4.8 to 5.3 swap ?

[mongocanfly]

I work with a guy that has a 4.8 auto truck and he's wanting to swap out to a 5.3...the question is he's thinking he can just swap the engine and ecm and be good to go..is this a doable swap or is there more to it..I've only done smallblock for ls swaps in older trucks..never a ls for ls swap in a newer truck..I'm not sure of the exact year models of his truck or his donor engine. I'm thinking mid 2000s on both