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

    MANLEY Rotating Assembly, 3.543 in. Stroke, 3.572 in. Bore Size, 5.933 in. Rod Length, -6.5cc Dish, For Ford 4.6L, Balanced, Kit

    MANLEY Rotating Assembly, 3.543 in. Stroke, 3.572 in. Bore Size, 5.933 in. Rod Length, -6.5cc Dish, For Ford 4.6L, Balanced, Kit

    $7,612.66

    QA1 27 Series Shock, Monotube, GM Full Size, Ford Mid & Full Size, Front, 3C/6R, Linear, Hyperscrew

    QA1 27 Series Shock, Monotube, GM Full Size, Ford Mid & Full Size, Front, 3C/6R, Linear, Hyperscrew

    $448.03

    Autometer Gauge, Tachometer, 5", 10K Rpm, Pedestal W/ Ext. Shift-Lite, Gs, Gs

    Autometer Gauge, Tachometer, 5", 10K Rpm, Pedestal W/ Ext. Shift-Lite, Gs, Gs

    $493.34

    COMP Cams Pushrod, Hi-Tech, Chromoly, Heat-Treated, One-Piece 8.800 in. Long, .135 in. Wall, 3/8 in. Diameter, Each

    COMP Cams Pushrod, Hi-Tech, Chromoly, Heat-Treated, One-Piece 8.800 in. Long, .135 in. Wall, 3/8 in. Diameter, Each

    $34.99

    Premium Piston Ring Set

    Premium Piston Ring Set

    $98.57

    ARP Main Studs, 2-Bolt Main, For Chevrolet 1954-62, 235, 261, L6, Kit

    ARP Main Studs, 2-Bolt Main, For Chevrolet 1954-62, 235, 261, L6, Kit

    $185.19