This is for the Jeep truck. I'm leaning towards 6.17's or 7.17 gear ratio. I don't plan on driving it too much on the road, but when I do I would like to be able to do at least 55 mph under 6k rpm lol. I did run the numbers on a gear calculator and looks like with the over drive gear in the 700r4 and running 42" tires it should run around 2200 rpm's at 55 and it would give me a crawl ratio around 75:1.