ARP 144-3605 Head Bolt Kit High Performance 8740 Chrome Moly

The ARP 144-3605 Head Bolt Kit delivers professional-grade cylinder head fastening with high-strength 8740 chrome moly steel construction. Designed for high-performance and competition engines, this kit features hex head bolts rated at 200,000 psi tensile strength—significantly stronger than standard Grade 8 fasteners.

Key Features:

• Premium 8740 chrome moly steel alloy construction
• 200,000 psi tensile strength for superior clamping force
• Heat-treated in vertical racks for complete, uniform heat penetration
• Centerless ground for exceptional concentricity and straightness
• Thread rolled after heat-treat for 10x better fatigue strength
• Hex head design with wide-area flange eliminates need for valve train removal during retorquing
• Includes hardened, parallel-ground washers for even load distribution and accurate torque readings
• Cold-forged to ensure molecular integrity

Engineering Advantages:

ARP's precision manufacturing process ensures that cylinder heads and gaskets align perfectly during assembly. The post heat-treat thread rolling process significantly improves fatigue resistance compared to pre-heat-treat threading methods used by other manufacturers. Select applications feature undercut short bolts that provide more uniform stretch characteristics, compensating for head gasket compression and helping prevent gasket failures.

The reduced wrenching hex head with wide-area flange allows cylinder head retorquing without removing valve train components, making maintenance faster and easier. This design also accommodates larger diameter valve springs for performance applications.

Installation Note:

After initial installation and torquing, fasteners should be re-torqued after the engine has been run to compensate for head gasket compression and ensure optimal clamping force.

Each fastener is stamped with the ARP logo as assurance of quality and adherence to ARP's zero-defect, zero-failure manufacturing standard. Trusted by professional engine builders across all forms of motorsports.