If he used stock explorer springs, that will only make a 1-2" drop total (with the spring under axle). Add the Chevy shackles, and it will actually be raised about an inch (varying on your model, the springs, how many leaves, etc.).
Glad you put it on aight. You probably have the 2WD rear ABS, and you should be fine. Everything should be working alright if it's all mounted properly.
Did you take measurements off the old ranger axle? The exploder is going to be 1.5" longer per side, thus the mounting problem. Use a string or tape measure and be precise from the diffy out on both, and regarding the shock mounts. How are you relocating the spring perches???
How's pinion angle?
1997 4.0L V6 XCab 4WD, 6" Suspension, 3" Body, 35x12.50x15 on 15x10 w/ 4.88's