ARP 135-4006 High Performance Cylinder Head Stud Kit Chrome Moly - 8740

The ARP 135-4006 head stud kit delivers professional-grade cylinder head fastening using premium 8740 chrome moly alloy steel rated at 200,000 psi—far exceeding aircraft quality standards. These high-performance studs are the choice of top engine builders for competition and high-performance applications where reliability is non-negotiable.

Superior Manufacturing Process:

• Precision heat-treated vertically in specialized racks to ensure complete and uniform heat penetration to 200,000 psi
• Centerless ground after heat-treat for exceptional concentricity and straightness, ensuring perfect alignment of gaskets and cylinder heads
• Thread rolled after heat-treat for approximately 1000% better fatigue strength compared to pre-heat-treat threading
• Specially undercut shorter studs equalize stretch characteristics for more consistent clamping force across all fasteners

Key Features:

• 8740 chrome moly steel construction with 200,000 psi tensile strength
• Hex head design with wide-area flange eliminates valve train removal for cylinder head retorquing
• Includes hardened parallel-ground washers for even load distribution and accurate torque readings
• Cold-forged to ensure molecular integrity and meet ARP's zero-defect quality standard
• Each stud stamped with ARP for authenticity assurance

Studs vs. Bolts: Studs provide superior performance for most applications by ensuring proper head and gasket alignment during assembly. Unlike bolts that twist under torque and react to multiple forces simultaneously, studs stretch only on the vertical axis when torqued, providing more accurate and consistent clamping force. Install studs finger-tight in relaxed mode, then torque the nut for optimal results.

Installation Note: Re-torque all studs after initial engine operation to compensate for head gasket compression and ensure optimum sealing performance.