My rig started off life as a 85 with the 2.5L.
The biggest downer is the fact that it is computer controlled carb. That Carter YFA is a PIA. I got real good at dealing with it and can offer support if you have problems, but I converted to the computer and tbi injection from the 86. I also did headers and the purple MOPAR cam. It did a good job wheeling but here at altitude it lacked guts on the mountain passes. I did however like the 28mpg.
I ended up building a 4.0L stroker and putting it in. Talk about night and day performace.:doh:
If possible, make sure and get the 5 speed. Most likely it will have 4.10 gearing.
You can put in a 4.0L but it means replacing the tranny as well. You also have to swap the computer, wiring hood, front facia, cross member, and radiator. A BFH will modify the firewall to clear the head.