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ARP 400-8509 High-Performance Chrome Moly Washer with Chamfer

Manufacturer

ARP

<h3>The Gold Standard in Performance Fasteners</h3> <p>When racing enthusiast Gary Holzapfel recognized that fastener failure was causing many engine breakdowns in 1968, he founded Automotive Racing Products (ARP) to solve a critical problem in motorsports. Drawing on his aerospace fastener manufacturing experience, Holzapfel created a company that would revolutionize the performance fastener industry. Today, ARP stands as the world's premier manufacturer of high-strength bolts, studs, nuts, and specialized hardware for racing and high-performance applications.</p> <p>ARP controls all aspects of the manufacturing process in-house, with all operations closely monitored, enabling the company to maintain its reputation for zero-defect quality. Every fastener undergoes forging, heat treatment, thread rolling, and precision finishing at ARP's Southern California facilities, which span over 115,000 square feet. This vertically integrated approach ensures that each component meets exacting standards for strength, fatigue resistance, and reliability under extreme conditions.</p> <h3>Engineered for Championship Performance</h3> <p>ARP's customer roster reads like a who's who of professional motorsports. The product line ranges from quality high-performance OEM replacement parts to exotic specialty hardware for Formula 1, IndyCar, NASCAR and NHRA drag racing and marine applications. The company's fasteners have secured victories in virtually every major racing championship worldwide, from Top Fuel dragsters to Formula One cars, proving their worth under the most demanding conditions imaginable.</p> <p>The brand's <a href="/48-arp-engine-cylinder-head-bolt-set-10306">engine cylinder head bolt sets</a> represent the cornerstone of ARP's catalog, offering engine builders the clamping force and reliability needed to prevent head gasket failure in high-boost and high-compression applications. These precision-engineered fasteners utilize proprietary materials and heat treatments that deliver up to ten times the fatigue strength of conventional bolts, making them essential for any serious performance build.</p> <p>For engine internals, ARP manufactures <a href="/48-arp-engine-connecting-rod-5276">connecting rods</a> designed to withstand extreme cylinder pressures and high RPM loads. Each rod is manufactured to aerospace standards with tight tolerances and superior material properties. Whether you're building a street performance engine or a full competition powerplant, ARP connecting rods provide the strength and consistency that professional engine builders demand.</p> <h3>Complete Fastener Solutions</h3> <p>Beyond engine components, ARP's product range extends throughout the entire vehicle. The company's <a href="/48-arp-wheel-lug-stud-7680">wheel lug studs</a> offer critical safety and performance benefits for racing and high-performance street applications, providing greater clamping force and durability than factory studs. ARP's product line contains thousands of part numbers and has expanded to include virtually every fastener found in an engine and driveline.</p> <p>Individual <a href="/48-arp-engine-cylinder-head-bolt-5308">engine cylinder head bolts</a> are also available for custom applications or specific replacement needs, manufactured to the same exacting standards as complete sets. This flexibility allows builders to source exactly what they need for specialized builds or repairs without compromising on quality.</p> <p>What sets ARP apart is not just the breadth of their catalog, but their willingness to develop custom solutions for unique applications. The company maintains complete R&D capabilities, including metallurgical research, product design, prototype machining, and extensive laboratory testing. This engineering expertise ensures that whether you're installing a simple head stud kit or building a record-setting race engine, ARP fasteners deliver the reliability and performance that professionals trust.</p>

Part Number

400-8509
08/02/2036 7:22 AM
Sale Price

$3.00

In Stock (10+)

delivery box

Usually delivered within 2 days

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No Hassle Returns

No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The ARP 400-8509 is a precision-engineered, single-piece high-performance washer featuring an inside diameter (I.D.) chamfer. Manufactured by ARP (Automotive Racing Products), this washer is built to the exacting tolerances demanded by professional engine builders and performance enthusiasts alike.

Constructed from premium chrome moly steel, this washer is parallel-ground to ensure consistent thickness and a perfectly flat seating surface. It is then hardened for superior strength and finished in a durable black oxide coating for corrosion resistance.

Key Features:

  • Single-piece construction for maximum integrity
  • I.D. chamfer for clean, precise fastener seating
  • Premium chrome moly steel construction
  • Parallel-ground for consistent thickness and flatness
  • Hardened for superior load-bearing strength
  • Black oxide finish for corrosion resistance
  • Available in a variety of sizes and thicknesses

ARP washers are an essential component when assembling performance engines, providing a reliable load-bearing surface that protects cylinder head and component surfaces from fastener pull-through or galling. Engineered to complement ARP studs and bolts, they ensure proper clamp load distribution across critical joints.

Products specifications

Hardened

No

Inside Diameter Chamfer

Yes

Quantity

Sold individually.

Size (ID/OD)

7/16 / 0.812

Thickness

.120?

Washer Finish

Natural

Washer Inside Diameter (in)

0.438 in.

Washer Inside Diameter (mm)

11.125 mm

Washer Material

Stainless steel

Washer Outside Diameter (in)

0.813 in.

Washer Outside Diameter (mm)

20.650 mm

Washer Thickness (in)

0.120 in.

Washer Thickness (mm)

3.048 mm

Had then part I needed for a great price!

1st order. Shipped super fast and prices are amazing. I will be back for sure.

Great customer service. Quick process and shipped les than 24hrs after order. 5 stars.

Autoplicity had exactly the part I was looking for, for my SRT8 Challenger, at the best price I could find!

Wish there were better product description. In the description it said there is a Carbon Fiber version, but no link. Would of been interested in that up sell to the CF Version. Do you even Carry this version, how much, and how to find it ? Also there w

Quick, cheap, and accurate. What else do you need?

Great prices and FAST shipping!! Definitely will buy products here again!

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