circle track rear gear ratio info needed
Mcodecuda’s suggestion is a good and the simplest place to start. A more complicated but more accurate solution for your car would be to find out what the top speed is for the class and track you plan on racing on. Then use an online gear calculator to determine what ratio will have your engine hit that speed just below your 6,200 RPM redline.
If you are using an automatic trans then be sure to allow some extra RPM for some slippage of the converter. You are limited to the available gear ratios so select the closest one to your calculated needed ratio while still leaving some RPM available to go faster if you can find more power in your engine. Keep in mind you can use slightly different size tires to adjust your gear ratio, as needed. Good luck and I’ll say it is always nice to see someone running a mopar in the sea of chevys at the races!