The ARP 208-4308 is a high-performance head bolt kit featuring premium 8740 chrome moly steel construction with 12-point heads. Designed for serious performance applications, this kit delivers the exceptional strength and reliability that professional engine builders demand.
Premium 8740 Alloy Construction:
ARP manufactures these fasteners from premium grade 8740 chrome moly alloy rated at 200,000 psi—far superior to aircraft quality materials. Each component is vertically rack heat-treated to ensure complete and uniform heat penetration, resulting in consistent strength throughout every fastener.
Precision Manufacturing Process:
- Centerless ground for exceptional concentricity and straightness
- Thread rolled after heat treatment for 10x better fatigue strength
- Cold-forged to ensure molecular integrity
- 12-point head design with wide-area flange for easy retorquing
- Reduced wrenching hex eliminates need for valve train removal
- Includes hardened parallel-ground washers for even load distribution
Engineering Advantages:
The precision manufacturing ensures that cylinder heads and gaskets align perfectly during installation. The 12-point head with wide-area flange allows for cylinder head retorquing without removing valve train components, making maintenance faster and easier. Select applications feature undercut short bolts that provide more uniform stretch to compensate for head gasket compression, helping prevent blown gaskets and ensuring optimal engine sealing.
Installation Notes:
These fasteners provide more accurate and consistent torque loading compared to standard bolts. The kit includes hardened parallel-ground washers to ensure even load distribution and accurate torque readings. Always re-torque after initial engine operation to compensate for head gasket compression.
Trusted by leading professional engine builders across all forms of motorsports, ARP fasteners represent the gold standard in engine assembly hardware. Each component is stamped with the ARP logo as your assurance of quality and meets ARP's zero-defect, zero-failure quality standard.