Header Bolts

Black Oxide Finish; 3/8"-16 Thread Diameter, 1" Long
5/16-inch Thread; 2 Inch Length
  • High-Quality Steel
  • Includes Lock Washes and Nuts
  • 2-inch Length
  • Sold as One Set of 4 Pieces
PART# 66342
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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.

  • Black Oxide Finish
Attribute Value