Wedge-Locking Header Bolts Hex Head M8 X .984 Inch Chevy LS Nickel Plt 12 Pcs Proform Exhaust Header Gasket 3/8-16 Inch x 1 Inch

3/8-16 Inch x 1 Inch Long

Same Holdowns As 66291

Compatible With PROFORM LS Slant-Edge Valve Covers

41:1 gear reduction

Wedge-Locking Header Bolts Hex Head M8 X .984 Inch Chevy LS Nickel Plt 12 Pcs Proform Exhaust Header Gasket 3/8-16 Inch x 1 InchEach 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