ARP 134-3604 High Performance Cylinder Head Bolt Kit Chrome Moly - 12-Point 8740

The ARP 134-3604 High Performance cylinder head bolt kit delivers professional-grade reliability for demanding engine applications. Engineered from premium 8740 chrome moly steel and rated at 180,000 psi—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 rated at 180,000 psi tensile strength
• 12-point head design with wide-area flange for easy installation and removal
• Allows cylinder head retorquing without valve train removal
• Cold-forged for molecular integrity and superior strength
• Heat-treated prior to thread rolling for optimal fatigue resistance
• Thread rolled after heat treatment for approximately 10 times better fatigue strength
• Centerless ground for precise concentricity and proper gasket alignment
• Includes hardened parallel-ground washers for even load distribution and accurate torque readings
• Reduced wrenching profile accommodates larger diameter valve springs

Manufacturing Excellence:

ARP's precision manufacturing process sets the industry standard. Each fastener is vertically rack heat-treated to ensure complete and uniform heat penetration throughout the material. The centerless grinding process involves multiple precision cuts to achieve exceptional straightness and concentricity, ensuring cylinder heads and gaskets align perfectly during assembly. Thread rolling is performed after heat treatment—a more expensive process that dramatically improves fatigue life compared to pre-heat-treat threading.

Application Notes:

These high-performance head bolts are ideal for street performance, racing, and competition engines where maximum reliability is required. The 12-point head design and wide flange eliminate the need to remove valve train components for routine maintenance or retorquing. For optimal performance, always retorque fasteners after initial engine operation to compensate for head gasket compression.

Backed by ARP's commitment to zero defects and zero failures, the 134-3604 head bolt kit represents the choice of professional engine builders across all forms of motorsports.