is the front coil or torsion bar?
if its coils, the rear won't have any blocks. so adding a rear block would work.
if its torsion bar you probably already have rear blocks, get bigger ones.
there is a difference in rear shock lengths, coils up front mean shorter shocks out back.
I had air lift shocks on my 05 2wd for a while, didn't like them at all.
with the shocks being inside the frame, it sorta acted like a center pivot point and allowed the truck to rock side to side despite the rear stabilizer bar. Even tried separate the air lines for each side.
I eventually installed beefier rear springs and gained about 3/4 " unloaded.