http://www.grimmjeeper.com/gears.htmlTry using that calulator. I like it because you can input all your ratios affecting your final drive ratio with your current set up then put your new proposed set up next to it to see what RPM's you'll be running with a different tire/gear combo at different speeds while being able to easily compair it to what your current set up gives you.
Aside from that, 4.10s are a good choice as you can get a 4 Cyliner Dana 30 that will already have 4.10's cheap. Kirk did this swap to make it easier for him and it works well on his 35's. He also used a 8.8 already geared to 4.10's, so his swap into the YJ was almost a bolt in.
If you went that way, you'd only have to re-gear the rear to 4.10's and would have a spare Dana 30 you could strip for trail spares. I have 33's on mine with the stock 3.73's and it still runs good. Its a little underpowered on the highway, but the supercharger makes up for it. I also have a Dana 44 rear locked that I will be selling soon if your interested.
