You're going to need a lot of auxiliary parts. Wiring harness and PCM, exhaust, fan and shroud, motor mounts, bellhousing (if you swap the tranny), etc, etc, etc...
There are a lot of threads on the 2.5 to 4.0 swaps. Take a brief look through them.
If it's worth doing, then it's worth [I]over[/I]doing.
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The build, the gear, and the mileage: [URL="http://www.jeepforum.com/forum/f22/wasteland-survival-guide-engineering-greta-1344782/"][B]The Wasteland Survival Guide[/B][/URL]