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
  • .984-inch Length
  • Fits GM LS Engines with 1/4-inch Wide Flange
  • PROFORM Parts Brand Product
  • Sold as Set of 12
  • More From This Category

    Proform , Starter Shim Kit , Fits Part Nos. 66256, 66258, 66259, 66266, 66267

    Proform , Starter Shim Kit , Fits Part Nos. 66256, 66258, 66259, 66266, 66267

    $20.31

    Proform , Ford Small Block Mustang Oil Pan, 7 Qt. Capacity

    Proform , Ford Small Block Mustang Oil Pan, 7 Qt. Capacity

    $400.22

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

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

    $207.94

    Proform , Electric Water Pump Adapter Kit , Converts Big-Block Chevy to GM LS

    Proform , Electric Water Pump Adapter Kit , Converts Big-Block Chevy to GM LS

    $271.28

    Proform , Chevy Chrome Timing Tab Small Block 8" Balancer, Features Easy-to-Read Marks for Accurate Timing

    Proform , Chevy Chrome Timing Tab Small Block 8" Balancer, Features Easy-to-Read Marks for Accurate Timing

    $9.38