I built a 3" body lift (non-suspension) for my 89 out of some 3" "C" channel and some 3" pipe, 1" pipe and some 1/8" plate (to make washers for the top & bottom of the 3" pipe.
I used longer 1/2" grade 8 bolts and simply added the 3" tall spacers under the original cab mounts (between the frame mounts and rubber body pucks.
had to cut the bottom section of the fan shroud, add a chunk of flat bar to the parking brake cable mount (right under the front door so the cable would reach) pointing up.
the steering column slid apart just above where it mounts to the steering box.
Massaged the brake lines a bit to extend them (just carefully re-bent them).
Under the box I used the "C" channel mounted it across the frame rails where the box mounts (3 bars used) and moved the clips on the frame to the top of the channel, box bolted on like they where not even there.
The gas fill was a bit of a challange, I live where it gets REAL cold ( minus 40) so simply "stretching" the top of the fuel tank was out of the question.
I found some pipe (both inner and outer hose sizes (you will see what I"m talking about when you remove the hose from the top of the tank.)
I carefully cut the hose(s) so that they left enough at the filler neck that I could insert the new pipe(s) as extensions used an extra 2 hose clamps on each pipe/hose connection and "TA-DA" extended the filler tube.
I made custom brackets for the bumpers, so they ride at the same height as the body (instead of being 3" lower, at the original location).
All in all, about 100 bucks worth of parts , a bit of welding, and a weekend........
Oh, the 1" pipe is a "crush-proof" spacer inside the 3" pipe, I welded the 1" pipe to one of the homemade washers, then welded the washer to the 3" pipe, then covered that with a 2nd washer, again welded to the 3" pipe. (made a tall "hockey puck" spacer with a 1/2 hole through the centre.)
Greg