ARP 155-4201 High Performance Cylinder Head Stud Kit Chrome Moly - 8740

The ARP 155-4201 cylinder head stud kit delivers professional-grade fastening performance for high-performance and competition engines. Manufactured from premium 8740 chrome moly alloy rated at 200,000 psi, these head studs provide superior clamping force and reliability far exceeding standard head bolts.

Key Features:

• Premium 8740 chrome moly steel construction rated at 200,000 psi tensile strength
• 12-point head design for positive engagement and reduced risk of rounding
• Centerless ground after heat treatment for exceptional straightness and concentricity
• Thread rolled after heat-treat for up to 10 times better fatigue strength
• Specially undercut shorter studs equalize stretch for consistent clamping force
• Includes hardened parallel-ground washers for even load distribution
• Vertical rack heat-treatment ensures complete and uniform heat penetration

Why Choose Studs Over Bolts:

Head studs provide superior performance compared to bolts because they stretch only on the vertical axis during torquing, eliminating the twisting forces that bolts experience. This results in more accurate and consistent torque loading. The precision manufacturing ensures that cylinder heads and gaskets align perfectly during assembly, making installation easier and more reliable—especially critical for racing engines requiring frequent servicing.

Installation Notes:

Install studs finger-tight in relaxed mode—never force them in with a jammed nut. Apply torque only to the nut, allowing the stud to stretch uniformly. Always re-torque after initial engine run-in to compensate for head gasket compression.

Trusted by professional engine builders across all forms of racing, ARP head studs represent the highest quality fastening solution available. Each stud is stamped with the ARP logo as assurance of zero-defect, zero-failure manufacturing standards.