ARP 151-4702 Cylinder Head Stud Kit - 8740 Chrome Moly Undercut Studs 12-Point

The ARP 151-4702 Pro Series cylinder head stud kit delivers professional-grade engine fastening performance using premium 8740 chrome moly steel construction. These competition-quality studs are engineered for high-performance and racing applications where reliable cylinder head clamping force is critical.

Key Features:

• Premium 8740 chrome moly alloy steel rated at 200,000 psi tensile strength
• Undercut studs for equalized stretch and consistent clamping force across all fasteners
• 12-point nuts with wide-area flanges for easy retorquing without valve train removal
• Thread rolled after heat treatment for superior fatigue strength
• Centerless ground for exceptional straightness and precise alignment
• Includes hardened parallel-ground washers for accurate torque readings
• Vertical rack heat treatment ensures complete penetration and uniform strength

Why Choose Studs Over Bolts:

Head studs provide superior clamping accuracy compared to bolts because they stretch only along the vertical axis during torquing, while bolts experience both torsional and tensile forces simultaneously. This results in more consistent and accurate torque loading. Studs also simplify engine assembly by allowing cylinder heads and gaskets to align properly without fighting fastener placement. The undercut design on shorter studs equalizes stretch rates across all fasteners, compensating for head gasket compression and helping prevent gasket failures.

Manufacturing Excellence:

Each ARP stud undergoes precision heat treatment in vertical racks to ensure uniform strength throughout the material. After heat treating, studs are centerless ground through multiple precise cuts to achieve exceptional concentricity and straightness. Thread rolling is performed after heat treatment—a more expensive and demanding process that delivers approximately ten times better fatigue strength compared to pre-heat-treat threading methods used by competitors.

ARP Pro Series head studs are the choice of professional engine builders across all forms of motorsports. Each stud is stamped with the ARP logo as verification of quality and backed by ARP's zero-defect, zero-failure quality standard.

Note: Always retorque studs after initial engine operation to compensate for head gasket compression.