Wedge-Locking 
Header Bolts

Black Oxide Finish; 3/8"-16 Thread Diameter, 3/4" Long
Fits Select 16 Bolt 3/8" Diameter Applications
Features:
  • Grade 8 (12.9) Steel
  • Hex Head Type
  • 3/4-inch Length
  • Fits GM BB 396-502 exc 348 and 409, Ford 5.0L, SB 289-302-351W, Mopar 413
  • Sold as One Set of 16 Pieces
PART# 66752
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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.

  • 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.
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