sounds like death wobble
It is possible the front hanger was not installed square or the shackles were misaligned.
have you checked your tie rod ends? wheel bearings? if it was a trail gear kit their spring bushings have short lives. how about the steering box? An 89 has a 28 year old box and may need to be rebuilt. There is a locking nut on the steering with a straight slot screw in it that can sometimes be used to tightened the steering. Tires balanced correctly? any wear on them to indicate alignment issues
There is a ton of crap that can go wrong..
pics can tell a thousand words...