Made my BL (3"), even made the front and back bumper brackets also.
One thing to remember, IF you live where it gets cold (like me), the fuel filler will NOT, I repeat, NOT, reach the panel behind the door.... IT might in summer, BUT, will NOT in a cold winter (OR expect to be replacing the fuel tank, because the neck of the tank got ripped off.........
I carefully cut the original hoses (both the inner and outer) in such a way that I had a short stub to insert a couple lengths (again BOTH inner and outer hose) of pipe and used stainless hose clamps to clamp it all up. I went 2" in extension to get to the panel behind the fuel door.
As well I did a chunk of 1" x 1/4" flat bar about 3" long to raise the P-Brake mount on the frame, so everything worked nicely.
Steering column was a PITA, but a 2-3/4" welded in section between the back of the box flange and the lower set of splines (removed and welded in the vise). worked well.
the front , middle and rear (cab) are three different length bolts (BUT, the 3" lifts are all the same) the bolts go through different sections of body/floor and some have thicker areas, as well as the rubber mounts themselves are different heights.
Check the steel mounts on the frame when the cab is off, you might find the DR rear with missing or badly rusted rivets......
The box, I used some 3" "C channel" going across the frame rails in 4 positions (even though there are only 3 sets of bolts on each side), (there's a blind support just in front of the rear axle), drilled both webs of the c-channel at each end, bolted them to the frame, and used the original frame clips on the top web of the c-channel and original box bolts.
Bumpers, front is a chunk of L shapped 1/4" plate, rear has an over the frame (instead of under slung) class 4 receiver for towing (this way it's tight to the bottom of the bumper, instead of hanging in "space" (looked real weird that way......)
Greg