Wedge-Locking Header Bolts – Proform (66754)

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.
Engine Header Bolts
Wedge-Locking Technology
Hex Head Type
M8 Thread X.984 Inch Long
Shiny Nickel Plated
12.9 Steel
12 Pcs in kit
Fits GM LS Engines with 1/4in Wide Flange
Header Bolts
Hex Head
M8 X.984″L
Exhaust Header Bolt
Wedge-Locking Header Bolts
Hex Head
M8 X.984in
Chevy LS
Nickel Plt
12 Pcs

Specifications

Vehicle Fitment