It wouldn't be worth the trouble to move a 4.0l 05 engine into an 04, unless you have 5-10k worth of extras into your 04 already, it would be much better to sell off your 04 and just buy a newer one. I bet you could do the swap for 5k or so, interestingly on the aftermarket there is not a huge difference between 04 and 05 but there is a HUGE difference in the vehicle itself. There is more than just 100 more horses in the 05', it is just overall a far superior truck.