Might be better off swapping in an I6 from a wrecked Jeep, I had a buddy swap an engine into his '92 F150 and it put him back a lot at some Nashville shop
Contact Tipton4x4 up in Munford and talk to BJ. They are known mostly for lifts/axles/gears/bolt ons but they do take on some cool builds. I have seen a diesel powered YJ, as well as, a few Hemi Powered JKs in the shop and they just dropped an LS into an S-10 for a shop truck
If he can't do want your looking at he can probably recommend someone local. Your biggest problem is most likely not going to be finding someone to do the work but going to be getting the parts (motor, adapters, harness, etc....).
Tipton - (901) 734-8016,