ARP (Automotive Racing Products) is the world leader in high-performance engine fasteners, manufacturing ultra-high-tensile head studs, main stud kits, rod bolts, and driveline hardware. Engineered in-house from 8740, ARP2000, and Custom Age 625+ alloys with threads rolled after heat treatment, ARP components eliminate head lifting, main cap walk, and bolt stretch under extreme horsepower and boost pressures.

Why Choose ARP Fasteners?

  • THREADS ROLLED AFTER HEAT-TREAT

    ARP rolls fastener threads after heat-treating rather than before, resulting in up to 10 times higher fatigue strength and superior thread engagement under load.

  • PROPRIETARY HIGH-TENSILE ALLOYS

    Manufactured in-house using premium 8740 Chrome Moly, ARP2000, and Custom Age 625+ alloys rated up to 260,000+ PSI tensile strength to eliminate stretch and head lifting.

  • PREVENT BLOCK & CAP FLEX

    Precision centerless-ground studs deliver accurate clamping force, eliminating main cap walk, protecting engine block threads, and maintaining perfect head gasket sealing.

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ARP: Frequently Asked Questions (FAQ)

What is the difference between ARP 8740, ARP2000, and Custom Age 625+ material grades?

8740 Chrome Moly is rated at 200,000 PSI tensile strength, making it an ideal upgrade over OEM hardware for high-performance builds. ARP2000 is rated at 220,000 PSI and offers increased resistance to stress corrosion. Custom Age 625+ reaches over 260,000 PSI, engineered specifically for high-boost, extreme-cylinder-pressure diesel and drag racing applications.

Why should I choose ARP head studs over factory head bolts?

Head studs provide a more consistent and accurate clamping force because they do not twist into the block threads during torquing like traditional head bolts. This eliminates thread friction inside the block, compensates for head gasket compression, and prevents blown head gaskets under high boost.

Do I need to use ARP Ultra-Torque Fastener Assembly Lube during installation?

Yes. ARP Ultra-Torque fastener lube ensures consistent friction between threads and under-head surfaces, allowing you to achieve the exact target preload and clamping force without under-torquing or over-stretching the fastener.

Are ARP main studs better than main bolts?

Main studs eliminate main cap walk and fret by providing exact alignment and higher clamping loads. They also protect sensitive cast-iron and aluminum block threads from wear during repeated engine teardowns.

Can ARP head studs and rod bolts be reused?

Yes. Unlike factory torque-to-yield (TTY) bolts that permanently stretch and must be discarded after one use, high-strength ARP studs and bolts are reusable as long as they have not exceeded their yield strength or stretch tolerances.