Engineered specifically for 2011 through 2026 Ford F-250, F-350, F-450, and F-550 Super Duty trucks powered by the 6.7L Powerstroke V8 turbo diesel engine, the ARP Custom Age 625+ Head Stud Kit (Part # 250-4302) represents the absolute pinnacle of high-tensile fastener technology for extreme horsepower and high-boost race applications. In competition diesel builds utilizing aggressive dual-high-pressure fuel pumps, massive compound turbochargers, and heavy nitrous or fueling calibration schedules, peak cylinder pressures soar far beyond standard performance levels.

While standard 8740 chromoly studs (such as standard ARP 250-4301 kits) provide excellent clamping force for street and moderate towing tunes, extreme combustion pressures can still cause microscopic stud elongation and head lift. ARP solves this by manufacturing the 250-4302 using Custom Age 625+ super-alloy steel, an advanced nickel-cobalt formulation originally engineered for aerospace turbine applications. Heat-treated prior to precision thread rolling and centerless grinding, Custom Age 625+ delivers an unyielding 260,000 PSI minimum tensile strength, offering superior fatigue resistance, thermal stability, and elasticity retention under punishing thermal loads.

The complete kit includes thirty-six Custom Age 625+ main studs, nine auxiliary ARP2000 M8 studs, forty-five 12-point chrome moly steel nuts, forty-five parallel-ground hardened washers, and a tube of ARP Ultra-Torque assembly lubricant with zero core charge.

Key Features & Benefits

• 260,000 PSI Minimum Tensile Strength: Forged from advanced Custom Age 625+ super-alloy steel to eliminate fastener stretch under extreme cylinder pressures.
• Aerospace Nickel-Cobalt Alloy: Exceptional high-temperature fatigue resistance and corrosion immunity designed specifically for high-output competition diesel engines.
• Complete 45-Piece Fastener Set: Includes 36 primary Custom Age 625+ studs and 9 auxiliary M8 ARP2000 studs to secure all cylinder head mounting points.
• Roll-Threaded After Heat Treatment: Maximizes cyclic fatigue life and eliminates root stress risers for ultimate clamping reliability.
• Hardened 12-Point Nuts & Washers: Precision-machined, parallel-ground chrome-moly hardware ensures uniform clamping load distribution and prevents galling.
• ARP Ultra-Torque Lubricant Included: Supplied with specialized assembly lube to guarantee accurate, friction-corrected torque preload.
• Zero Core Charge: Brand-new outright professional competition hardware requiring no core deposit or core return shipping.

Technical Specifications

• Manufacturer / Brand: Automotive Racing Products (ARP)
• Manufacturer Part Number / SKU: 250-4302
• Alternative Part Numbers: ARP-250-4302 / ARP2504302 / CA625+ 6.7 Powerstroke Studs
• Product Series: Pro Series Custom Age 625+ Cylinder Head Stud Kit
• Fastener Material: Custom Age 625+ Nickel-Cobalt Super-Alloy Steel
• Tensile Strength Rating: 260,000 PSI Minimum
• Kit Component Breakdown:
  • (36) Custom Age 625+ Primary Cylinder Head Studs
  • (9) Auxiliary M8 ARP2000 Fasteners
  • (45) Chrome Moly Steel 12-Point Flange Nuts
  • (45) Parallel-Ground Hardened Washers
  • (1) Pack ARP Ultra-Torque Fastener Assembly Lubricant
• Truck Platform: 2011–2026 Ford Super Duty (F-250, F-350, F-450, F-550)
• Engine Platform: 6.7L Powerstroke V8 Turbo Diesel (Gen 1, Gen 2, and Gen 3 Platforms)
• Core Requirement: None
• Warranty: ARP Limited Manufacturer Warranty

Vehicle Fitment & Technical Installation Notes

• 2011–2026 Ford F-250 Super Duty – 6.7L Powerstroke V8 Turbo Diesel
• 2011–2026 Ford F-350 Super Duty – 6.7L Powerstroke V8 Turbo Diesel
• 2011–2026 Ford F-450 Super Duty – 6.7L Powerstroke V8 Turbo Diesel
• 2011–2026 Ford F-550 Super Duty – 6.7L Powerstroke V8 Turbo Diesel
• Fits Model Years: 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025, 2026
• Thread Preparation Prerequisite: Clean every blind threaded hole in the engine block meticulously using an M12 thread chaser and compressed air. Removing all oil, debris, and carbon is mandatory to prevent false torque readings and block cracking caused by fluid hydro-locking.
• Installation Tip: Thread studs into the engine block hand-tight only. Liberally coat the upper threads, washer faces, and nut mating surfaces with the provided ARP Ultra-Torque lubricant. Follow Ford's factory spiral torque sequence in incremental multi-step passes to achieve precise clamp load without distorting cylinder bore roundness.