ARP 207-4701 Cylinder Head Stud Kit High Performance Chrome Moly - 8740

The ARP 207-4701 head stud kit delivers professional-grade fastening performance for high-performance and competition engines. Manufactured from premium 8740 chrome moly steel and heat-treated to 200,000 psi, these studs provide exceptional strength and durability that exceeds aircraft-quality standards.

Key Features:

• Premium 8740 chrome moly steel construction rated at 200,000 psi tensile strength
• Precision heat-treated vertically in racks for complete, uniform heat penetration
• Centerless ground to exacting tolerances for superior concentricity and straightness
• Thread rolled after heat-treatment for 10x better fatigue strength compared to pre-heat-treat threading
• 12-point heads for secure engagement and easy installation
• Undercut shorter studs equalize stretch for consistent clamping force across all fasteners
• Includes hardened, parallel-ground washers for even load distribution and accurate torque readings

Superior Manufacturing Process:

Each ARP stud undergoes a meticulous manufacturing process that sets it apart from competitive offerings. The vertical heat-treat process ensures complete heat penetration throughout the material. Following heat-treatment, each stud is centerless ground through approximately ten precise cuts, resulting in exceptional straightness and concentricity. This exacting tolerance allows cylinder heads and gaskets to align perfectly during installation.

Undercut Design Benefits:

The engineered undercut on the shorter studs equalizes stretch characteristics between fasteners of different lengths, providing more consistent clamping force across the entire cylinder head. This design compensates for head gasket compression during installation, helping prevent blown head gaskets and ensuring optimal engine sealing under extreme conditions.

Studs vs. Bolts:

Head studs offer significant advantages over bolts for most applications. Studs should be installed finger-tight in a relaxed state, then torqued via the nut. This allows the fastener to stretch only along the vertical axis when torque is applied, eliminating the twisting forces that occur with bolts. The result is more accurate and consistent torque loading. Studs also simplify engine assembly by ensuring proper alignment of the cylinder head and gasket. Note that studs should be re-torqued after initial engine operation to compensate for head gasket compression.

Trusted by professional engine builders across all forms of motorsports, ARP Pro Series head studs represent the pinnacle of fastener technology for serious performance applications.