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

    Proform , Carburetor Base Plate 850/950/1050 CFM, Mechanical Secondary; Made from Quality Billet Aluminum

    Proform , Carburetor Base Plate 850/950/1050 CFM, Mechanical Secondary; Made from Quality Billet Aluminum

    $463.62

    Proform , Air Bleed Tuning Kit for High-Speed System, Includes No. 65 through No. 75 Air Bleeds (4 of Each)

    Proform , Air Bleed Tuning Kit for High-Speed System, Includes No. 65 through No. 75 Air Bleeds (4 of Each)

    $125.62

    Proform , 2-1/2" Diameter Exhaust Collector Gasket Kit, 3 Hole Type; Made from Soft Conforming Aluminum

    Proform , 2-1/2" Diameter Exhaust Collector Gasket Kit, 3 Hole Type; Made from Soft Conforming Aluminum

    $31.61

    Proform , Radiator System, Slim-Fit, 1979-93 Mustang/Cougar, 1980-88 Thunderbird, Fox Body Mustangs with Manual Transmission

    Proform , Radiator System, Slim-Fit, 1979-93 Mustang/Cougar, 1980-88 Thunderbird, Fox Body Mustangs with Manual Transmission

    $1,775.85

    Proform , 8" Harmonic Balancer Chevy Big Block 396, Fits Chevy Big Block 396 Engines

    Proform , 8" Harmonic Balancer Chevy Big Block 396, Fits Chevy Big Block 396 Engines

    $234.67