Exact same story happened to us. Dealer told us same story. Ended up tearing it down ourselves not sure if it was headgaskets or injector cups. Sure enough it ended up being injector cup leaking.
Good luck!
I'm not sure what you classify my comment as, but an '01 will not be an LBZ, it's an LB7. :D
As far as the transplant goes, I have no idea. Let the ideas begin!
I tried to take a pic with my camera phone, but it didn't turn out clear enough to tell what the fuses were. I'll try to borrow a camera & get a clear pic if somebody doesn't beat me to it. :)