Charlie, remount the rear shocks in front of the axle housing. When they're behind it all they do is just get pulled out when the springs wrap up in the front. Also use a pinion stubbed to limit rearend shift. You also might need stuffer rear springs to mak the suspension work. Light weight rims make a big difference. Weld draglites only weigh about 11-13#. Steel factory weigh about 20-28#. Less weight to slow the movement of the tires. Also mark the tires and rims to make sure the tires aren't rotating on the rims. Tire pressure will effect the times to.