ARP 134-3608 Cylinder Head Bolt Kit Chrome Moly Steel - 8740

The ARP 134-3608 High Performance Series cylinder head bolt kit delivers professional-grade clamping force and reliability for demanding engine builds. Manufactured from premium 8740 chrome moly steel and heat-treated to 180,000 psi tensile strength—15% stronger than Grade 8—these fasteners provide the durability needed for high-performance applications.

Key Features:

• Premium 8740 chrome moly steel construction with 180,000 psi tensile strength
• Hex head design with wide-area flange for even load distribution
• Allows cylinder head retorquing without valve train removal
• Thread rolled after heat treatment for superior fatigue resistance
• Includes hardened parallel-ground washers for accurate torque readings
• Precision heat-treated using vertical rack process for complete penetration
• Centerless ground for exceptional straightness and alignment

Manufacturing Excellence:

ARP's exacting manufacturing process sets these fasteners apart. Each bolt is vertically rack heat-treated to ensure uniform properties throughout, then centerless ground through multiple precision cuts to achieve near-perfect 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 Benefits:

The precision tolerances of ARP fasteners ensure cylinder heads and gaskets glide into perfect alignment during assembly. The wide-area flanged head design eliminates the need to remove valve train components when retorquing, saving valuable time during engine maintenance and allowing compatibility with larger diameter valve springs.

Each kit includes hardened parallel-ground washers to ensure even load distribution and accurate torque readings. For optimal head gasket sealing, re-torque fasteners after initial engine run-in to compensate for gasket compression.