What little I've learned from racing a Buick GN -
If you have coil springs in the back (showing my ignorance here) install air bags - at least on the passenger side.
Put a level on your rear bumper and have a buddy watch it while you push on the brake and the gas at the same time.
Play around with the air pressure until the level is - level. That should pre-load the right rear.
I know a guy who has a tubbed out '72 that runs 11's. If you have some questions, I can ask him how he does it.
Bet it involves $.
