ARP 155-3603 High Performance Cylinder Head Bolt Kit 8740 Chrome Moly

The ARP 155-3603 High Performance Series cylinder head bolt kit delivers professional-grade fastening strength for demanding engine applications. Manufactured from premium 8740 chrome moly steel and heat-treated to 180,000 psi tensile strength—15% stronger than Grade 8 fasteners—these head bolts provide superior clamping force and durability for high-performance and racing engines.

Key Features:

• Premium 8740 chrome moly steel construction for exceptional strength and fatigue resistance
• Heat-treated to 180,000 psi tensile strength, exceeding Grade 8 specifications
• 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
• Thread rolled after heat treatment for superior fatigue life and thread integrity
• Precision manufactured to exacting tolerances for perfect cylinder head alignment

Manufacturing Excellence:

ARP's advanced manufacturing process ensures each fastener meets the highest quality standards. Head bolts are cold-forged to maintain molecular integrity, vertically rack heat-treated for complete penetration, and precisely machined to ensure concentricity. The thread rolling process occurs after heat treatment—a costly but critical step that provides approximately ten times better fatigue strength compared to pre-heat-treat threading methods used by other manufacturers.

Installation Notes:

The flanged hex head design allows for convenient cylinder head retorquing without removing valve train components, making maintenance faster and easier. Because head gaskets compress during initial torquing, always re-torque fasteners after the engine has been run to ensure optimal clamping force and seal integrity.

This kit is designed for engine builders who demand zero-defect reliability and maximum performance from their fastening systems. Each component is manufactured to ARP's exacting standards, ensuring proper gasket compression, consistent clamping force, and long-term durability in high-stress applications.