Click to zoom in
SKU: 301-8400 | UPC: 672036045357
ARP M12x1.25 8740 Black Oxide 12-pt Nut Kit (25 Pack)
Secure your high-performance engine builds with the ARP M12x1.25 12-point nut kit featuring 8740 chrome moly steel construction and black oxide finish. These nuts fit ARP head studs and main studs on popular engines like Subaru EJ-series in WRX STI Impreza and Honda K20 K24 in Civic Si RSX. Rated at 180,000 PSI tensile strength they handle extreme torque and heat in racing or street applications.
Key Features
- 8740 Chrome Moly Steel: Forged for 180,000 PSI tensile strength to withstand high cylinder pressures and boost levels
- 12-Point Design: Delivers 12 contact points for positive wrench grip and prevents fastener rounding during high-torque assembly
- Black Oxide Finish: Provides corrosion resistance and reduced friction for smoother installation and long-term durability
- Thick Wall Construction: Ensures maximum rigidity and strength in space-available applications like cylinder heads and mains
- 25-Piece Kit: Bulk quantity covers full engine sets or spares for Subaru EJ Honda K-series and other M12x1.25 setups
Product Notes
- Confirm M12x1.25 thread match on your ARP studs before ordering
- Store in dry conditions to maintain black oxide protection
- Kit arrives sealed for protection during transit
Installation Notes
- Professional installation recommended.
- Apply ARP Ultra-Torque assembly lube to threads and under nuts for precise torque values
- Directly compatible with ARP head studs mains and rod bolts in M12x1.25 applications
This Part Fits
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2002-2007 | Honda | Civic | Si (EP3 K20A3) |
| 2002-2006 | Acura | RSX | Type-S (K20A2) |
| 2006-2011 | Honda | Civic | Si (K20Z3) |
| 2004-2021 | Subaru | Impreza | WRX STI (EJ25) |
| 2002-2007 | Subaru | WRX | (EJ20 EJ25) |
| 1999-2005 | Mitsubishi | Lancer | Evolution (4G63) |
Why Choose ARP?
- Trusted by NHRA Top Fuel and Formula 1 teams for mission-critical fastening
- Every nut forged heat-treated and machined to exacting tolerances
- Made in USA with rigorous quality control for reliability in every build
Frequently Asked Questions
-
Q: What thread specification do these nuts fit?
A: Precisely threaded M12 x 1.25 to match ARP metric studs in head main and accessory applications -
Q: How many nuts come in this kit and what is the material?
A: Kit includes 25 nuts made from premium 8740 chrome moly steel with 180,000 PSI rating and black oxide coating -
Q: What warranty does ARP provide?
A: ARP warrants against manufacturing defects with replacement coverage when installed and torqued correctly
Shipping & Handling
- Method: UPS Ground
- Availability: In stock - ships same or next business day
- Packaging: Compact protective box 6 x 4 x 1 inches
- Weight: 0.31 lbs
ARP Head Studs
ARP head stud kits for internal engine builds are stocked at Black Ops Auto Works. Shop ARP head stud and bolt kits, main stud kits, and rod bolt kits engineered for HEMI, Ford Modular and Coyote, GM LS, Subaru EJ, Honda K and B series, VW/Audi turbo four cylinders, Porsche, BMC, and Renault engines, along with the Ultra-Torque assembly lubricant every kit depends on. Every product is filterable by year, make, model, and engine platform so the correct fastener kit ships the first time. Black Ops Auto Works carries 812 ARP Head Studs SKUs across 8740 chromoly and ARP2000 alloy options. What This Collection Covers ARP head studs replace factory head bolts with precision-machined threaded studs that thread into the block and allow the nut to be torqued concentrically on a stationary fastener, producing more even and repeatable clamping force across the entire head gasket surface than a factory head bolt design. This collection focuses on the internal engine fasteners that hold the ...
View ARP Head Studs Products
Hardware
Engine hardware, fasteners, and mounting hardware kits for builds, fabrication, and suspension work are stocked at Black Ops Auto Works. Shop ARP engine bolts and stud kits, suspension mounting hardware from Fox and Rock Krawler, bumper mount kits, tie rod clamps, joint retainer tools, and single and kit-packaged hardware for domestic, import, and off-road platforms. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 945 Hardware SKUs across engine hardware, suspension mounting hardware, and single-piece or kit-packaged fasteners. What This Collection Covers Hardware groups together the fasteners, mounting kits, clamps, and small components that hold engines, suspension systems, and accessories together. This includes ARP engine hardware such as intake manifold bolts and cam bolt kits, suspension mounting hardware from Fox and Rock Krawler for shock and steering stabilizer installs...
View Hardware Products
Hardware Kits - Other
Hardware kits and fastener assortments for engine builds, suspension installs, body and trim jobs, and off road rigs are stocked at Black Ops Auto Works. Shop ARP bolt and stud kits, brake caliper hardware, suspension bushing hardware, leaf spring hardware kits, security fastener kits, and general clip and retainer assortments across domestic and import platforms. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 593 Hardware Kits - Other SKUs across engine, suspension, body, and lighting hardware categories. What This Category Covers The Hardware Kits - Other category groups together fastener kits and hardware assortments that do not fall under a single dedicated part category. Coverage spans engine fastener kits like cam bolts and intake manifold bolts, suspension hardware including bushing pivot washers and leaf spring hardware, seat belt mounting hardware, security hardware fo...
View Hardware Kits - Other Products