In over my head.... HELP!

[Materman]

Back a few months ago I decided to thrust myself I to the strange new world (to me anyway) of LS swapping my '72 GMC Sprint (el Camino) but now I realize I'm not sure what to do....
Here's my issue:

I bought a 5.3 with wiring harness and ECU out of a wrecked '08 Silverado 4x4 z71, I would really like to rewire/Repin the wiring harness myself, but cannot find a schematic for the newer E38 ECU, only for the older computers. I also was told that my '99 4l60e I have for this project will not work because its a '99 2wd tranny and I have a '08 wiring harness for a 4x4 tranny. Question #1: is there ANY wiring how-to's out there on the new harness? Question #2: will my tranny work somehow and if so, what do i need to do?

Any suggestions/help is really appreciated because I'm really starting to reconsider this whole mess!

Thanks, Richard