ARP Custom Age 625+ Head Stud Kit (260-4704) | Subaru WRX 2002-2014 / STI 2004-2021

The ARP Custom Age 625+ Head Stud Kit (260-4704) is engineered to provide exceptional clamping strength and durability for Subaru EJ20 and EJ25 engines in WRX and STI applications. Utilizing ARP’s advanced **Custom Age 625+ super-alloy**, these head studs deliver significantly higher tensile strength, fatigue resistance, and corrosion resistance compared to traditional fastener materials — making them ideal for high-horsepower, high-boost, and high-RPM builds where enhanced head sealing integrity is critical.

KEY FEATURES

• Custom Age 625+ super-alloy head studs provide superior strength, toughness, and fatigue resistance
• Designed specifically for Subaru EJ20 and EJ25 DOHC engines to improve head-to-block sealing
• Premium 12-point nuts and parallel-ground washers for precise torque and consistent clamping
• Enhanced corrosion and oxidation resistance for long-term reliability
• Ideal for boosted, high-power, and motorsport engine builds

TECHNICAL SPECIFICATIONS

• Part Number: 260-4704
• Fastener Material: Custom Age 625+ super-alloy for high tensile strength and fatigue life
• Socket Size: 9/16″ 12-point and 3/16″ Allen
• Included Hardware: 12 head studs, 12 parallel-ground washers, 12 premium 12-point nuts
• Design Intent: Dramatically increase clamping force compared to stock head bolts for increased sealing integrity under performance conditions
• Application: Subaru EJ20 and EJ25 DOHC engines

VEHICLE FITMENT

• Subaru WRX 2002–2014
• Subaru STI 2004–2021
• Subaru Forester XT 2004–2013
• Subaru Legacy GT 2005–2012
• Subaru Outback XT 2005–2009

PRODUCT NOTES

• This kit includes head studs, washers, and 12-point nuts only; related engine hardware such as main studs and block bolts are not included.
• Custom Age 625+ super-alloy offers a tensile strength typically in the range of 260,000–280,000 psi for superior clamping and fatigue life.
• Proper installation using ARP assembly lubricant, torque sequence, and torque specifications is critical for achieving optimal clamping force and reliability.

ARP delivers precision-engineered, high-strength fasteners and hardware solutions trusted by professional builders, racers, and performance enthusiasts worldwide for uncompromising reliability, durability, and repeatable performance in demanding automotive and motorsports applications.