welcome and nice 88 shorty.

I have a 88-440 truck that I used an A-body 8 3/4 with a shackle flip to tuck 12" wide/4.5 backset welds with a 29x15x15 M/T

I did have to tubb the bed flush with the frame but it was a bolt in.

if you want to keep the stock width truck axle and tubb the bed flush with the frame, you can use a 10" wide rim with a 7.5 backset to tuck a 29x15x15 M/T in the fenders with a set of long drop shackles to lower the rear of truck.

if you do not want to tubb the bed, you can fit a 10" wide rime with 4.5 backset and run a 275/60/15 without lowering the truck and not poke out the fender (maybe slighty past the wheel well lip)

you should be able to get a 10" rim with the 5 on 5.5 wbp and either 4.5 /7.5 backset to fit the stock axle.

if it is a 10 bolt rear axle you can swap the axle for sbp wheels

the 12 bolt is a little more effort to swap wbp with the c-clip/sidegear change to the 9 1/4 12 bolt axles.

a C-body (74 Newport) 8 3/4 is the same width as a stock truck axle so that is a bolt in with sbp axles and only need the spring perches moved/welded in place.

the A-body 8 3/4 shares the same 43" spring perch centers and bolt in on top of spring in the truck using car shock plates/u-bolts along with a shackle flip.

a 94 cheerokee rear axle has the 43" spring perch centers and is the same width as the A-body axle..and it bolt in under spring like the stock truck axle..this will tuck 12 with 29 M/Ts also. you can get a limited slip diff with a 3.73-4.10 gear ez-pz and hold up to a fair amount of street duty.

here is what a shackle flip looks like, you use a front rear spring hanger to replace the stock truck hanger on the back. flip the shackle and bolt axle on top of the springs like a car/DAK chassis.