If you are considering an engine and tranny swap, go to the Novak site and spend some time in the knowledge base. When you know what motor you want to go with research it's power band - most V8's like to run at much lower RPM than your 4 banger. Then, figure out the final drive ratio of your engine, tranny, tcase combo and what size tires you will likely run, use the calculator - Novak Conversions - Gearing & Gearing Math for Jeeps
to decide what gears put you in the correct RPM range for the speeds that you will drive. This is not something to guess at. I had geared to 4.56 before my engine swap, so it was essential for me to use a tranny with a good overdrive so that my motor wasn't screaming at highway speeds.