ARP 400-8312 Stainless Steel 12-Point Nut Kit M8 x 1.25 Polished Universal

Vehicle Fitment

Universal - no specific vehicle fitment. Suitable for any application requiring M8 x 1.25 replacement or upgrade nuts, including cylinder head studs, intake manifold studs, exhaust manifold studs, accessory brackets, and general engine and chassis fastening applications.

Fitment Notes

• Thread size is M8 x 1.25 right-hand thread - verify your stud or bolt uses M8 x 1.25 before ordering
• Wrench size is 10mm - confirm clearance for a 10mm 12-point socket in your application
• Stainless steel construction is recommended for exhaust, coolant, and other high-heat or high-moisture environments where chromoly nuts may corrode
• For the same size in black oxide chromoly (8740 steel), see ARP 300-8312
• All ARP stainless nuts are right-hand thread - confirm thread direction of your application

Features

• Made from ARP Stainless 300 series stainless steel - impervious to rust, corrosion, and discoloration in exhaust and coolant environments
• Rated at 180,000 psi tensile strength - substantially stronger than OEM hardware nuts
• 12-point profile provides better socket engagement in confined spaces compared to standard 6-point hex nuts, reducing the risk of rounding under torque
• Thick wall construction for maximum strength and rigidity under sustained clamping loads
• Polished finish delivers a clean, show-quality appearance on visible engine components
• Meets ARP's internal quality standards - manufactured to the same specifications as the nuts included in ARP stud and bolt kits

Specifications

• Part Number: 400-8312
• Material: ARP Stainless 300 Series
• Tensile Strength: 180,000 psi
• Thread Size: M8 x 1.25
• Thread Direction: Right-Hand
• Nut Style: 12-Point
• Wrench / Socket Size: 10mm
• Finish: Polished
• Self-Locking: No
• Fitment: Universal
• Quantity: Set of 10

Included Components

• 10x ARP Stainless 300 M8 x 1.25 12-Point Nuts

Product Description

The ARP 400-8312 is a universal replacement and upgrade nut kit for M8 x 1.25 threaded studs and bolts. ARP's stainless 12-point nuts are the standard replacement hardware for worn or corroded nuts on head studs, exhaust manifold studs, intake manifold studs, accessory brackets, and any other M8 x 1.25 fastening application. They are also the correct replacement nuts for ARP stud kits that use M8 x 1.25 studs, ensuring the full fastener assembly maintains its rated strength and material consistency.

Made from ARP Stainless 300 series material at 180,000 psi, these nuts resist corrosion in high-heat and high-moisture environments where standard hardware fails. The 12-point profile fits a 10mm socket and provides superior engagement in tight engine bay locations. Sold as a set of 10 polished stainless nuts - no washers included.