Mopar Head Bolt Kit - 5.7/6.1L Hemi

The ARP Mopar Head Bolt Kit for 5.7/6.1L Hemi engines (Part Number 147-3901) is a professional-grade fastener assembly engineered for Gen III Hemi cylinder head applications. Manufactured from chromoly steel with black oxide finish, this 12-point head design delivers the clamping force and material integrity required for high-performance and boosted engine builds where OEM fasteners fall short of structural demands.

ARP's Pro Series specification means this kit meets the standards used in professional racing and extreme-duty applications. The chromoly construction resists fatigue and stretch under sustained high cylinder pressures, while the black oxide coating provides corrosion resistance in engine bay environments. The 12-point head geometry allows precise torque control during installation and is less prone to rounding compared to 6-point alternatives. This bolt kit is the OEM replacement for Mopar Gen III Hemi platforms and ensures proper head gasket sealing and block deck integrity across the full RPM and boost range.

Users building or rebuilding 5.7L (340 hp base and performance variants) or 6.1L (425 hp) Hemi engines rely on this kit when replacing head gaskets, performing machine work, or fortifying the engine for forced induction. Installation requires a torque wrench capable of the Hemi-specific specifications and proper sequencing to ensure even clamping load across all cylinders. This is an essential component for Dodge, Chrysler, and Jeep Hemi platform owners planning serious powerplant work.