If you have an open differential (non-posi), one of the easiest ways to equalize traction on both rear tires is to install an air shock on the right rear only and experiment with air pressure until you get 2 equal black marks under acceleration. A front-motor, rear drive vehicle twists the chassis on a wedge so that the left front and the right rear get light, the right front and the left rear get heavy. That's why you always see the right rear tire spinning. Once you've got the weight equalized, bolt some cheater slicks on it for Saturday night games and you'll be one more step ahead.