Each Grade 8 Header Bolt is permanently assembled with a pair
of special washers. When the bolt is torqued to 28+ ft-lbs, the
washers’ super-hardened external teeth bite into and grip the bottom of
the bolt head and the top surface of the header. After being
self-locked in this manner, any bolt-loosening rotation is blocked by a
wedge-locking action created by the washers’ interfacing, matching cams.
It’s an uphill climb: vibration that might ordinarily loosen the bolt
actually increases the wedge-locking tension, securing the bolt even
more. Because this simple wedge-locking method uses tension instead of
friction, contact with oil actually facilitates the wedge effect.
changing headers, these Header Bolts can be untightened with a normal
wrench, lubricated, and reused.