I just switched a '98 from diesel to gas and it was not easy....yours won't need as much to change but you need under hood wiring in order for the 4wd to work as you have wiring going to the front diff and transfer case....installing the 4wd harness with the engine in (at least with a 7.4L) is extremely tight...

 

Right now I have a whole lot of room under the hood, even with the 350. I was hoping to find a manual setup if at all possible, but if not wouldn't GM use the same wiring harness for 2x4 and 4x4 models?

 

with the '98 it has the shifter on the floor rather than electric push button however you still need the 4x4 wiring as the 4x2 does not have that in the harness

 

where did you get the 4" lift kit and how much was it?