ARP 135-3704 Cylinder Head Bolt Kit Chrome Moly Steel - 8740 12-Point

The ARP 135-3704 High Performance Series head bolt kit delivers professional-grade fastening strength for demanding engine applications. Engineered with premium 8740 chrome moly steel and heat-treated to 180,000 psi tensile strength—15% stronger than Grade 8 fasteners—these bolts provide reliable cylinder head clamping force under extreme conditions.

Advanced Manufacturing Process:

• Cold-forged construction ensures molecular integrity and superior fatigue resistance
• Precision heat-treatment process with controlled vertical racking for complete, even heat penetration
• Thread rolling performed after heat-treat for approximately 1000% better fatigue strength compared to pre-heat-treat threading
• Centerless grinding creates exceptionally straight, concentric fasteners for perfect head and gasket alignment

Key Features:

• 12-point head design for positive engagement and reduced risk of rounding
• Wide-area flanged head eliminates need for valve train removal during cylinder head retorquing
• Hardened, parallel-ground washers included for even load distribution and accurate torque readings
• Select applications feature undercut short bolts to equalize stretch and compensate for head gasket compression
• Each fastener marked with ARP stamp as assurance of quality

Installation Benefits:

The 12-point head and wide flange design allows cylinder head service without removing valve train components, saving significant labor time during maintenance. The reduced wrenching profile also permits use of larger diameter valve springs in performance applications. Hardened washers ensure consistent torque values and prevent embedment into softer materials.

ARP fasteners are the choice of professional engine builders across all forms of motorsports, delivering the zero-defect, zero-failure quality standard required for competition and high-performance street applications. These bolts provide the strength and reliability needed when engine integrity is non-negotiable.

Note: Always re-torque cylinder head fasteners after initial engine warm-up cycle, as head gasket compression will occur during the first heat cycle.