ARP 134-4307 Cylinder Head Stud Kit Chrome Moly - 8740 12-Point

The ARP 134-4307 is a high-performance cylinder head stud kit engineered for serious performance applications. Constructed from premium 8740 chrome moly steel and featuring 12-point heads, this kit delivers the superior clamping force and reliability that professional engine builders demand.

Premium 8740 Chrome Moly Construction:

ARP manufactures these studs from 8740 chrome moly alloy rated at 200,000 psi tensile strength—far exceeding aircraft-grade materials. Each stud undergoes precise vertical rack heat treatment to ensure complete and consistent heat penetration throughout the material, resulting in superior strength and durability compared to batch-processed fasteners.

Precision Manufacturing Process:

• Centerless ground after heat treatment for exceptional concentricity and straightness
• Thread rolled after heat treatment for approximately 1000% better fatigue strength
• Cold-forged to maintain molecular integrity
• 12-point head design with wide-area flange for easy retorquing without valve train removal
• Undercut design on shorter studs equalizes stretch for more consistent clamping force

Installation and Performance Benefits:

Head studs provide significant advantages over bolts for performance applications. Because studs are installed in a relaxed state and torqued via the nut, they stretch only along the vertical axis when torqued—unlike bolts which experience both torsional and tensile loads simultaneously. This results in more accurate and consistent torque readings and superior clamping force. The precision manufacturing ensures that cylinder heads and gaskets align perfectly during assembly, streamlining engine builds and rebuilds.

Each kit includes hardened, parallel-ground washers to ensure even load distribution and accurate torque readings. The undercut design on shorter studs helps prevent head gasket failures by providing additional stretch to compensate for gasket compression. This Pro Series kit meets ARP's zero-defect quality standard and is the choice of leading professional engine builders across all forms of racing.

Note: Studs should be installed finger-tight in a relaxed mode. After initial torquing and engine run-in, re-torque all fasteners to compensate for head gasket compression.