ARP 135-3611 Cylinder Head Fasteners 8740 Chrome Moly Hex Head Bolts

The ARP 135-3611 cylinder head fastener kit delivers professional-grade clamping force and reliability for high-performance engine builds. Engineered from premium 8740 chrome moly steel, these hex head bolts are heat-treated to 180,000 psi—approximately 15% stronger than Grade 8 fasteners—ensuring exceptional strength and durability under extreme cylinder pressure.

Key Features:

• Premium 8740 chrome moly steel construction rated at 180,000 psi tensile strength
• Cold-forged manufacturing process ensures molecular integrity and consistent material properties
• Precision heat-treatment with vertical rack placement for complete and uniform heat penetration
• Thread rolling performed after heat-treat for approximately 1000% better fatigue resistance
• Reduced wrenching hex head with wide-area flange eliminates need for valve train removal during retorquing
• Centerless ground for exceptional straightness and precise concentric tolerances
• Includes hardened parallel-ground washers for even load distribution and accurate torque readings
• Select applications feature undercut short bolts to equalize stretch and compensate for head gasket compression

ARP's exacting manufacturing standards ensure that cylinder heads and gaskets align perfectly during assembly, while the reduced hex design allows for easy access and retorquing without disassembling valve train components. The wide-area flanged head accommodates larger diameter valve springs common in performance applications.

Each fastener meets ARP's zero-defect quality standard and is individually inspected to ensure it delivers the consistent clamping force required for competition engines and demanding street/strip applications. Complete kit includes all necessary head bolts and hardened washers for proper installation.