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ARP 256-5701 Main Cap Fasteners



<p>Today, ARP&rsquo;s product line contains thousands of part numbers, and has expanded to include virtually every fastener found in an engine and driveline and throughout the suspension and frame. These range from quality high performance OEM replacement parts to exotic specialty hardware for Formula 1, IndyCar, NASCAR and NHRA drag racing and marine applications.</p>

Part Number

12/02/2033 12:36 PM
Sale Price


In Stock (10+)

delivery box

Usually delivered within 2 days

free shipping


No Hassle Returns

No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

ARP 256-5701 Main Cap Fasteners

The studs in this main stud kit are made from 8740 chromemoly steel and have 190000 psi tensile strength rating. They are precision centerless ground and thread rolled to Mil-S-8879 specs. They feature a black oxide finish hardened washers and hex nuts.

Main Stud Kit
4Bolt Main
w/ Windage Tray

Main Studs
There are many important reasons to use ARP main stud kits, including the elimination of main cap walk and fretting, as well as protecting the threads in your engine block. All kits come complete with hardened parallel-ground washers and high quality nuts. Some applications have provisions for mounting windage trays and have specially designed standoff studs with serrated lock nuts to position the windage tray and lock it securely in place. The studs are manufactured from 8740 chrome moly steel, heat-treated in-house to 200,000 psi tensile strength, and precision J-form threads rolled after heat-treat to create a fastener that has threads 1000% stronger than others.

Main Bolts
Far superior to any other main bolt kit offered for use in competition engines, ARP main bolts are designed to meet the exacting standards and demands of professional engine builders. Forged from 8740 chrome moly, all bolts feature generous under-head radius and rolled threads for the utmost reliability. The threads are rolled after heat-treating, which makes them about 1000% longer fatigue life than most main bolts, which are threaded prior to heat-treating. Available in the popular High Performance Series, which, at a nominal rating of 180,000 psi, is a premium replacement for OEM fasteners, or the 200,000 psi nominal rated Pro Series, application-specific main bolts with reduced wrenching head and are designed for use in competition applications. Parallel-ground, hardened washers are included with each kit.

Products specifications

Fastener Nut Style

Standard hex

Fastener Style


Fastener Yield Strength (psi)

200,000 psi

Main Bolt Style



Designed to fit with windage tray.

Nuts Included



Sold as a kit.

Washers Included


Works with Windage Tray



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Great so far

Fast & easy

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Was a good service thank you....

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Cheap cat, cheap shipping. We'll see when it gets here!

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I bought a Bestop for my Samari and the service was great and the top fit perfect. The online site is easy to use and quick.

The item has not been delivered yet. But the email updates are great. And I found this much cheaper than elsewere.

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