If you have your heart set on replacing the motor you may want to look into a northstar. You can get the mua5 with the 60* gm bell. You should then be able to work out a way to install the northstar. 300 hp stock and its a popular motor so stand alone harness kits are easy to come by.

1987 trooper LS.'94 3.2, SAS,35's , lots of dents and rust. Now, improved, with more dents.
1995 trooper LS. Wife won't let me improve this one.
1996 trooper. I'll need something to modify when the '87 finally rusts away.