Rear segments should not be clamped and I agree with the earlier comment too be wary of too stiff a spring. That car needs body separation to plant the tires. Also, to get the suspension working you may try leaving at a lower RPM so the converter "flashes" off the line. You need that action of the rear axle housing trying to rotate which makes the front segment push the body up and as Newton said, every action has an equal and opposite reaction. I believe that will drop your sixty as long as you are hooking.