The " NUTS " for the " head bolts " They are a type of lock nut rite ? The ones I used when I went back up with the motor are regular nuts with a wider " washer type " base . But They keep viabrating off ! The base nuts also loosened up and blew out the base gasket . Before you ask , No I didn't torque them down . I can't find my d$mn torque wrench anywhere . So I just REALLY tightened them down .