ARP 2604704 Custom Age 625+ Cylinder Head Stud Kit

The ARP 2604704 Custom Age 625+ head stud kit delivers professional-grade cylinder head clamping performance for Subaru EJ20 and EJ25 DOHC engines. Engineered for high-performance and forced induction applications, this kit provides superior strength and reliability compared to factory head bolts.

Premium Custom Age 625+ Construction:

• Custom Age 625+ material provides exceptional strength and corrosion resistance
• Cold-forged construction ensures molecular integrity throughout each stud
• Heat-treated prior to thread rolling for maximum fatigue strength
• Precision centerless ground for near-perfect concentricity
• Thread rolled after heat treatment for superior fatigue resistance

Complete Kit Includes:

• Undercut head studs for improved gasket compression compensation
• 12-point nuts for precise torque application
• Hardened parallel-ground washers for even load distribution
• ARP Ultra-Torque fastener assembly lubricant

Key Benefits:

• Exacting tolerances allow cylinder heads and gaskets to align perfectly during installation
• Undercut design on short studs equalizes stretch for more consistent clamping force
• Eliminates head gasket failure from inadequate clamping pressure
• Ideal for turbocharged, supercharged, and high-compression builds

ARP head studs are the preferred choice of professional engine builders for competition powerplants where fastener failure is not an option. Each component is manufactured to ARP's zero-defect quality standard.