Wedge-Locking Header Bolts; Hex Head; M8 X 1.181in; Chevy LS; Nickel Plt; 12 Pcs | #66755

Header Bolts

Nickle Finish; M8 Diameter, 1.181" Long
Fits Select 12 Bolt 8mm Diameter Applications
  • Grade 8 (12.9) Steel
  • Hex Head Type
  • 1.181-inch Length
  • Fits GM LS Engines with 3/8-inch Wide Flange
  • PROFORM Parts Brand Product
  • Sold as One Set of 12 Pieces
PART# 66755
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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.

  • Wedge-Locking Technology Eliminates Constantly Re-Tightening Exhaust Collector Bolts; Blocks Bolt-Loosening Rotation caused by Vehicle Vibrations.
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