Each PROFORM 12.9 Steel (equiv. 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. It's 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
  • 1-inch Length
  • Fits GM BB 396-502 exc 348 and 409, Ford 5.0L, SB 289-302-351W, Mopar 413
  • PROFORM Parts Brand Product
  • Sold as One Set of 16 Pieces
  • More From This Category

    Proform , PROFORM Race Series 850 CFM Carburetor, Draw-Thru, 2x4 Supercharger Model

    Proform , PROFORM Race Series 850 CFM Carburetor, Draw-Thru, 2x4 Supercharger Model

    $2,040.00

    Proform , PROFORM Black Race Series 950 CFM Carburetor, Premium Black Teflon Finish

    Proform , PROFORM Black Race Series 950 CFM Carburetor, Premium Black Teflon Finish

    $1,824.63

    Proform , Super-Street Ford Aluminum Roller Rockers, For Ford 302, Boss 351C, 429-460 V8 Engines

    Proform , Super-Street Ford Aluminum Roller Rockers, For Ford 302, Boss 351C, 429-460 V8 Engines

    $568.85

    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