Other than your 1 wire running back to your fuel pump, and your couple plugs for O2's, that's pretty much it going under the truck. The only real thing back there that you may have to mess with is the crank sensor (FYI, I would recommend installing a new one before bolting it in the truck). But you do have just enough room to get that out of there with it in the truck. I had to do it multiple times on that old 8.1 that was in my truck. It was kinda annoying as I had to lay on top of the motor to get the little bolt out, and then reach my hand back there and pull that thing up and out. Sucked, but can be done. Shoot, I even changed the oil pressure sending unit on the back of there to one that would work with my factory square body oil pressure gauge with the motor in the truck (again, that kinda sucked, but I was able to do it). I would recommend changing that sending unit out with it out of the truck too (that is if you plan to use your stock square body gauges like I did)