65 vette has all new bushings and mounts. Heres the problem, the whole rear will shift and the pinion points upward and the driveshaft hits the tunnel. I fix the issue by removing the rear end and re-install it. My theory is that the bias ply tires had grip so the differential never torqued up, but with good radials gripping the road the pinion rides up and shifts the rear end. Has anyone else experienced this?