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 , 3000 Gram Digital Scale , 3000 Gram Capacity, 1 Gram Resolution

    Proform , 3000 Gram Digital Scale , 3000 Gram Capacity, 1 Gram Resolution

    $387.97

    Proform , 140 AMP Alternator Chrome Finish, 1-Wire, GM 10 SI; w/ Internal Regulator, V-Pully, & Ext. Fan

    Proform , 140 AMP Alternator Chrome Finish, 1-Wire, GM 10 SI; w/ Internal Regulator, V-Pully, & Ext. Fan

    $358.69

    Proform , 50-Amp Mini Alternator Chrome Finish, 1 Wire, Universal; 6 Lbs.

    Proform , 50-Amp Mini Alternator Chrome Finish, 1 Wire, Universal; 6 Lbs.

    $357.09

    Proform , High-Flow Water Pump Mechanical Long Style, Satin Finish; Made from High-Quality Aluminum

    Proform , High-Flow Water Pump Mechanical Long Style, Satin Finish; Made from High-Quality Aluminum

    $243.19

    Proform , Super-Street Chevy Aluminum Roller Rockers, 1.6 Ratio; 7/16" Stud

    Proform , Super-Street Chevy Aluminum Roller Rockers, 1.6 Ratio; 7/16" Stud

    $526.94