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Proform Wedge Locking Header Bolts

Item #: PFM66751

Price: $31.99



Fits: Mopar BB 383-440

Black Oxide Finish; 3/8"-16 Thread Diameter, 3/4" Long


Grade 8 (12.9) Steel

Hex Head Type

3/4-inch Length

Sold as Set of 12

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.