Wedge-Locking Header Bolts - Nickle Finish PR66755

Suit GM LS Series, M8 x 1.181" UHL (12-Pack)

PR66755

66755

Each PROFORM 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. Its 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. When changing headers, PROFORM Header Bolts can be untightened with a normal wrench, lubricated, and reused. Features: Grade 8 (12.9) Steel Hex Head Type 1.181-inch Length Fits GM LS Engines with 1/4-inch Wide Flange Sold as One Set of 12 Pieces