ARP 145-3901 High Performance Cylinder Head Bolt Kit Chrome Moly - 8740

The ARP 145-3901 High Performance Series cylinder head bolt kit delivers professional-grade engine fastening strength for demanding performance applications. Manufactured from premium 8740 chrome moly steel and heat-treated to 180,000 psi tensile strength—15% stronger than Grade 8—these hex head bolts provide superior clamping force and reliability for high-performance engines.

Advanced Manufacturing Process:

• Premium 8740 chrome moly alloy steel construction
• Precision heat-treatment to 180,000 psi tensile strength
• Thread rolled after heat-treatment for 10x better fatigue resistance
• Centerless ground for exceptional concentricity and alignment
• Cold-forged to ensure molecular integrity

Design Features:

• Reduced wrenching hex head design
• Wide area flanged head eliminates need for valve train removal during retorquing
• Hardened parallel-ground washers included for even load distribution
• Precision tolerances ensure cylinder heads align perfectly during installation
• Permits use of larger diameter valve springs

Performance Benefits:

• More accurate and consistent torque loading compared to standard bolts
• Superior clamping force helps prevent head gasket failures
• Easier engine assembly with assured gasket and head alignment
• Meets ARP's zero-defect, zero-failure quality standard

Each ARP fastener is manufactured to exacting tolerances using vertical rack heat-treatment for complete penetration and consistent results. The post-heat-treat thread rolling process significantly increases fatigue strength, while centerless grinding ensures each bolt is as close to perfectly straight as possible. Complete kit includes hardened washers for accurate torque readings and optimal load distribution.

Kit Includes: High Performance head bolts with hex heads and hardened parallel-ground washers.

Note: Always retorque fasteners after initial engine run-in to compensate for head gasket compression.