Likely not, as the 3.0 didn't show up until 88 in our rigs, so you'll be looking at fabbing your engine mounts to start.

A couple 3.0 to 3.4 links. I've consolidated some info, but we haven't gone live with it yet. Yes, ORS makes the kit; $$$$$

linky 1

linky 2

Also, BigMike did a 2.7L swap into his 1st gen rig over on Marlincrawler. Has the same ponies as the 3.0 at 150 hp; the next 4 banger after the 22Rx.

Use the 3.0 FSM in the sticky here, and one of the FSMs over in the Taco section for the 3.4 or 2.7 if you go for it.

Edit: Here's what ORS has on the subject:

http://www.offroadsolutions.com/technicalarticles.htm
and
http://www.offroadsolutions.com/products/engine_upgrades.htm