Traction Issues

The springs came clamped, so that's the way I left them. The U-bolts are torqued to 45 lbs./ft. The rear shocks are longer nonadjustable Mopar drag shocks. Stock T-bars with stock worn out shocks up front. This is the first time I've run this combo. It was about 42 degrees at the track. I tried 20, 18, 16 and 14 psi in the rear tires with about a 5 to 7 second burnout in first gear. Launching at 2500 bogged down the motor and 2750 spun the tires.