If you are driving the car to the track I would recommend a Detroit locker instead of a spool. I love them. I ran 4.86 with a 30 x 12.5 slick. My car is a 65 valiant. So I know its very light. 2850 with me in it. However I run a converter that flashes to 3800 rpm. With a 2.75 first gear ratio...