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
  • 3/4-inch Length
  • Fits GM V6, SB 265-400, Buick, Olds, Pontiac '79 and earlier, Mopar BB 383-440 exc 413, AMC V8's w 3/8" bolts
  • PROFORM Parts Brand Product
  • Sold as Set of 12
  • More From This Category

    Motive Gear Differential Master Bearing Kit, Koyo, For BUICK APOLLO 1973–1975, Kit

    Motive Gear Differential Master Bearing Kit, Koyo, For BUICK APOLLO 1973–1975, Kit

    $189.46

    Wilwood Caliper, FNSL4R, Radial, 0.81 in. Rotor Width, 14.00 in. Rotor Dia, 1.12/1.12 in. Bore, Universal, Alum, Red, Each

    Wilwood Caliper, FNSL4R, Radial, 0.81 in. Rotor Width, 14.00 in. Rotor Dia, 1.12/1.12 in. Bore, Universal, Alum, Red, Each

    $576.87

    FAST 2 Pack of 45 Degree Plug Boots and Terminals

    FAST 2 Pack of 45 Degree Plug Boots and Terminals

    $8.45

    Nitto Conrods I-Beam For Nissan SR20, 136.3MM (Use Wider GTi-R Bearings),  V2 Design, set

    Nitto Conrods I-Beam For Nissan SR20, 136.3MM (Use Wider GTi-R Bearings), V2 Design, set

    $1,460.00