GM LS series engines harmonic balancers came from the factory with a torque-to-yield style bolt. Torque-to-yield bolts are not designed to be reusable and should be discarded or the potential for failure can occur (example: twisting off in the crankshaft). When changing the balancer, camshaft, or any other part that requires removal of the balancer use an ICT Billet quality harmonic balancer bolt.