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 3/8-inch Wide Flange
  • PROFORM Parts Brand Product
  • Sold as Set of 12
  • More From This Category

    MANLEY Piston, 1.065 in. Compression Distance, 4.005 in. Bore Size, -31cc Dish, For Chevrolet LS, Set of 8

    MANLEY Piston, 1.065 in. Compression Distance, 4.005 in. Bore Size, -31cc Dish, For Chevrolet LS, Set of 8

    $1,892.22

    Nitto Stoker Kit for Nissan SR20 2.2L (I-Beam Rods/87mm Bore) - EN40B

    Nitto Stoker Kit for Nissan SR20 2.2L (I-Beam Rods/87mm Bore) - EN40B

    $6,935.00

    Crow Cams Camshaft, Holden V8 304/355 Carby Hydraulic Roller, Adv. Duration 303/307, Valve Lift 0.568/0.568

    Crow Cams Camshaft, Holden V8 304/355 Carby Hydraulic Roller, Adv. Duration 303/307, Valve Lift 0.568/0.568

    $997.16

    MANLEY Piston, Coated, Extreme Duty, 1.115 in. Compression Distance, 3.785 in. Bore Size, -7cc Dish, Coated, For Chevrolet 5.3L, Each

    MANLEY Piston, Coated, Extreme Duty, 1.115 in. Compression Distance, 3.785 in. Bore Size, -7cc Dish, Coated, For Chevrolet 5.3L, Each

    $298.95

    Premium Piston Ring Set

    Premium Piston Ring Set

    $175.68