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

    Proform , Primary & Secondary Linkage Kit, Kit includes Three Ratios

    Proform , Primary & Secondary Linkage Kit, Kit includes Three Ratios

    $26.40

    View
    Proform , Wireless Digital Mini RPM Shift Light, Black; 100 to 12,000 RPM Ranges; 1-12 cylinder range

    Proform , Wireless Digital Mini RPM Shift Light, Black; 100 to 12,000 RPM Ranges; 1-12 cylinder range

    $89.69

    View
    Proform , PERFECT LAUNCH GM 12 Bolt Differential Cover, GM, 12 Bolt Rear End; Black Finish; Reinforced aluminum

    Proform , PERFECT LAUNCH GM 12 Bolt Differential Cover, GM, 12 Bolt Rear End; Black Finish; Reinforced aluminum

    $300.17

    View
    Proform , Chevy HEI Distributor Blue Cap; w/o Vac. Adv., Nylon Lock-out

    Proform , Chevy HEI Distributor Blue Cap; w/o Vac. Adv., Nylon Lock-out

    $193.68

    View
    Proform , Chevrolet Performance Hold Down Clamps, Shark Gray Finish Chevy Hold-Down Clamps w/ Red Bowtie Logo

    Proform , Chevrolet Performance Hold Down Clamps, Shark Gray Finish Chevy Hold-Down Clamps w/ Red Bowtie Logo

    $40.87

    View
    Proform , Chrysler Distributor Black Cap, Fits Chrysler 361-383-400 V8 Engines

    Proform , Chrysler Distributor Black Cap, Fits Chrysler 361-383-400 V8 Engines

    $209.59

    View