ARP 131-4001 High Performance Cylinder Head Stud Kit Chrome Moly - 8740

The ARP 131-4001 is a high-performance cylinder head stud kit engineered for serious engine builders who demand maximum reliability and clamping force. Built from premium 8740 chrome moly steel and rated at 200,000 psi tensile strength, these studs deliver superior strength and fatigue resistance for high-performance and racing applications.

Advanced Manufacturing Process:

• Premium 8740 chrome moly alloy exceeding aircraft quality standards
• Vertical rack heat treatment ensures complete penetration and consistent 200,000 psi rating
• Centerless ground after heat treatment for precise concentricity and perfect alignment
• Thread rolled after heat treatment for 10x better fatigue strength than pre-hardened threading
• Undercut short studs (where applicable) equalize stretch for more consistent clamping force

Why Studs Over Bolts:

Head studs provide significant advantages over traditional head bolts. During installation, studs stretch only along the vertical axis when torqued, while bolts experience both torsional and tensile loads simultaneously. This results in more accurate and consistent torque readings with studs. Additionally, studs simplify engine assembly by allowing cylinder heads and gaskets to glide into perfect alignment. Each stud is installed finger-tight in a relaxed mode, then torque is applied only to the nut.

Kit Includes:

• Complete head stud set with hex nuts
• Hardened parallel-ground washers for even load distribution
• Assembly lubricant

Each stud is permanently marked with the ARP logo as your assurance of quality. Professional engine builders across all forms of motorsports rely on ARP Pro Series studs for competition powerplants where failure is not an option. Remember to re-torque after initial engine run as head gaskets will compress during the first heat cycle.