Its possible that they may. When you torque a bolt, the threads stretch and expand. TTY (torque-to-yeild) is another term for one-time use. Being that the head has tremendous pressures, I would play it safe and replace them, expecially after the rebuild you are doing. Doesnt hurt to do it right the 1st time.guy022077 said:Does torque to yield mean if i torque them again they may break?