Swapping a V6 for a V8

I am trying to swap out my 2001 GMC 4.3L V6 for a 2001 GMC 5.3L V8. I am wondering how intensive it will be and if it is even worth it. I am also wanting to keep my tranny because I think it will be compatible but will it be fully? And if not what will be lost? I also have the tow package option on my truck currently and want to know if the swap will effect it.

Thanks!