Rear suspension... HeLp
My buddy ran into the 9's before his 8-3/4 broke in a all steel 69 Dart with a Indy headed 500 in RB. Full interior. He did run a larger tire. Just sayin the 8-3/4 lived a long time in the 10's.
It was all done on SS springs.
Look into the racers forum where there is a current thread about 60' times on SS springs going on. Others pipe in about there suspension.