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 , Chevy HEI Distributor Red Cap, Fits Chevy 262 V6 Engines

    Proform , Chevy HEI Distributor Red Cap, Fits Chevy 262 V6 Engines

    $442.49

    View
    Proform , Digital Valve Spring Pressure Tester , 0-600 lbs Range, 5 lbs Measuring Increments

    Proform , Digital Valve Spring Pressure Tester , 0-600 lbs Range, 5 lbs Measuring Increments

    $595.15

    View
    Proform , Carburetor Studs Kit w/ Lock Washers & Nuts, Chrome Plated; Made from High-Quality Steel

    Proform , Carburetor Studs Kit w/ Lock Washers & Nuts, Chrome Plated; Made from High-Quality Steel

    $9.60

    View
    Proform , LS Valve Spring Compressor Tool , Fits LS1, LS2 and LS6 Cylinder Heads

    Proform , LS Valve Spring Compressor Tool , Fits LS1, LS2 and LS6 Cylinder Heads

    $126.29

    View
    Proform , 3-Piece Pushrod Set GM LS; Stock Length, 7.400"

    Proform , 3-Piece Pushrod Set GM LS; Stock Length, 7.400"

    $94.70

    View
    Proform , AMC HEI Distributor Red Cap, Fits AMC Inline 6 Cylinder 232-258

    Proform , AMC HEI Distributor Red Cap, Fits AMC Inline 6 Cylinder 232-258

    $442.49

    View