ARP 145-4007 Cylinder Head Stud Kit Chrome Moly Steel - 8740

The ARP 145-4007 is a premium quality cylinder head stud kit engineered for high-performance and racing applications. This Pro Series kit features ARP's legendary 8740 chrome moly steel construction with hex head design, delivering exceptional clamping force and reliability for demanding engine builds.

Premium 8740 Alloy Construction:

ARP manufactures these studs from premium grade 8740 chrome moly steel, rated at 200,000 psi tensile strength—far superior to aircraft quality fasteners. Each stud is vertically rack heat-treated to ensure complete and uniform heat penetration throughout the material, resulting in consistent strength characteristics that inferior basket-tumbled studs cannot match.

Precision Manufacturing Process:

• Centerless ground after heat-treat for exceptional concentricity and straightness
• Thread rolled after heat-treatment for 1000% better fatigue strength versus pre-heat-treat threading
• Cold-forged to maintain molecular integrity
• Undercut short studs equalize stretch for more consistent clamping force
• Each stud stamped with ARP marking for authenticity

Performance Advantages:

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 tolerances ensure cylinder heads and gaskets glide into perfect alignment during assembly, making engine builds faster and more reliable.

Complete Kit Includes:

• Premium 8740 chrome moly steel head studs
• Hardened parallel-ground washers for even load distribution
• Hex nuts for installation

Each kit is designed to ARP's zero-defect, zero-failure quality standard, making it the choice of professional engine builders across all forms of motorsports. The undercut design on shorter studs helps prevent head gasket failures by compensating for gasket compression when cylinder heads are installed, ensuring optimal engine sealing under extreme conditions.

Installation Note: Studs should be installed finger-tight in a relaxed mode—never cranked in tightly. Re-torque after initial engine run to compensate for head gasket compression.