ARP 134-4305 Head Stud Kit High Performance Series - 8740 12-Point

The ARP 134-4305 is a high-performance head stud kit engineered for serious engine builders who demand the ultimate in reliability and clamping force. Built from premium grade 8740 chrome moly steel and rated at 200,000 psi, this Pro Series kit delivers exceptional strength and durability for high-performance and competition applications.

Key Features:

• Premium 8740 chrome moly alloy rated at 200,000 psi for superior tensile strength
• 12-point head design with wide area flange for easier installation and removal
• Vertical heat treatment process ensures complete and consistent heat penetration throughout each stud
• Centerless ground after heat treatment for near-perfect concentricity and straightness
• Thread rolled after heat treatment for up to 10 times better fatigue strength
• Undercut short studs equalize stretch and provide more consistent clamping force
• Includes hardened, parallel-ground washers for even load distribution and accurate torque readings
• Allows cylinder head removal without valve train disassembly for easier maintenance

Why Choose Studs Over Bolts:

Head studs provide superior performance compared to bolts because they stretch only along the vertical axis when torqued, eliminating the twisting forces that affect bolts. This results in more accurate and consistent torque loading, better head gasket sealing, and easier engine assembly. Studs install finger-tight and are torqued via the nut, ensuring the fastener remains in a relaxed state during installation.

Manufacturing Excellence:

Each ARP stud undergoes precision manufacturing processes that set the industry standard. The vertical rack heat treatment method ensures uniform properties throughout the fastener, while the centerless grinding process involves approximately ten precision cuts to achieve exceptional straightness. This attention to detail ensures that cylinder heads and gaskets align perfectly during installation—a critical advantage in high-performance applications.

The undercut design on shorter studs helps equalize stretch characteristics across all fasteners, compensating for head gasket compression and helping prevent blown head gaskets. This engineered approach to fastener design is what makes ARP the choice of professional engine builders in all forms of racing.

Note: Always re-torque studs after initial engine run-in to compensate for head gasket compression and ensure optimal clamping force.