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 , Big Block Chevy Oil Dipstick & Tube Kit, Chevy Big Block 396 to 454 Engines

    Proform , Big Block Chevy Oil Dipstick & Tube Kit, Chevy Big Block 396 to 454 Engines

    $13.44

    View
    Proform , PROFORM Circle Track 650 CFM Carburetor, Gas, Circle Track Model

    Proform , PROFORM Circle Track 650 CFM Carburetor, Gas, Circle Track Model

    $1,467.36

    View