Installing new headers on your small block Chevrolet or V6 engine? These high-quality PROFORM header bolts (66751) are the perfect addition! Their locking design will securely hold them in place when installed.
Features and Benefits:
- 3/8”-16 thread diameter
- ¾ inch long
- fits GM V6 and 265-400 small block
- set of 12
Grade 8 Header Bolt is permanently assembled with a pair of special washers. When the bolt is torqued to 28+ ft-lbs, the washer's 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. Because this simple wedge-locking method uses tension instead of friction, contact with oil facilitates the wedge effect.
When changing headers, PROFORM Header Bolts can be untightened with a normal wrench, lubricated, and reused.
Vehicle Fitment: 1960-1987 C10