I posted in your other thread, but to my knowledge a 5.3 is not a direct bolt up engine for us. Something to consider is that our transmission is a 4L30E and is part of a series of transmission including the 4L60 and 4L80 both of which are beefier automatics. Ours is unique in the fact that we have the TOD transfer case mated directly to the transmission housing though. So what I'm getting at is you'll need a new transmission and transfer case. Length is also an issue as the 4l60 and 80 are both a lot longer. That's why many people usethe TH350 and TH400 as they are more suited to short wheelbase rigs. I know advance adapters makes kits for bolting up almost anything mainstream to anything else. Good luck, but in my opinion, you are fighting a lost cause if you are trying to accomplish this quickly with the amount of research and information you've got. FWIW pirate4x4.com has a lot of buildups and they match up all kinds of crazy combos so you can see what aroma together and what it's going into size wise. Be warned, they are not generally even close to as friendly and willing to help as this forum. They have the info, but they're a bit snobby and condescending about sharing it at times.