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.
  • Wedge-Locking Header Bolts
  • Hex Head
  • 3/8 dia. X 1in
  • Blk Oxide Finish
  • 16 Pcs
Applications Fits GM BB 396-502 exc 348 and 409, Ford 5.0L, SB 289-302-351W, Mopar 413
Category Header Bolts
Color Black Oxide
Country of Origin (Primary) TW
Emission Code Legal US
Feature/Benefit Backed by a full 30 day limited factory warranty.
Finish Black Oxide
Harmonized Tariff Code (Schedule B) 7318159000
Hazardous Material Code N
Life Cycle Status Code 2
Material Steel
NAFTA Preference Criterion Code B
Part Type Header Bolts
SDR Required Flag N

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PROFORM 66756 Wedge-Locking Header Bolts Hex Head 3/8” dia. X ¾

Product Information

  • Brand: Proform
  • Product Number: 66756
  • $33.99