I recently completed putting a 98 XJ 4.0 in my 89 Yj that had the 4 cyl. Major pain in the backside. You will have to change the transmission, not just because it won't match up, but because the AX-5 can't handle the power of a decent 6 cyl. I had to re-weld the engine mounts a different place on the frame,change tranny, t-case input, half the exhaust and then there was the wiring harness nightmare. For just a little bit more I could of had a V-8, but it is nice having something a little different. Any other questions e-mail me. [email protected]