I wouldn't even try this. Is a Gen 3 4x4 chassy that hard to find? All you need is the frame with steering and drivetrain!
not really, its about just as easy to make a 2wd truck a 4x4 as it is to SAS a IFS 4x4
the 89-95 trucks are so different underneath that none of the steering or front axle would be usuable on the SAS anyway