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ARP 135-2501 Harmonic Balancer Bolt Kit for Chevy Big Block

Manufacturer

ARP

<h3>About ARP – Automotive Racing Products</h3><p>Few names carry as much weight in the performance fastener world as <strong>ARP</strong> — short for Automotive Racing Products. Back in 1968, racing enthusiast Gary Holzapfel noticed that many of his friends' broken engines were caused by fastener failure, and at the time no commercially available studs or bolts were up to the challenge — so he drew on his years of experience as a leading aerospace subcontractor and founded ARP. That problem-solving spirit has driven the company ever since.</p><p>From a backyard garage workshop, ARP has grown into a highly diversified manufacturer with 18 buildings across Southern California, totaling more than 275,000 square feet of forging, heat-treating, machining, quality control, finishing, and packaging facilities in Santa Paula and Ventura, California.</p><h3>Engineering That Goes Beyond &quot;Aerospace Quality&quot;</h3><p>ARP uses only top-quality materials — far above the usual &quot;aerospace quality&quot; others settle for — in a highly exacting manufacturing process to create fasteners with the strength and durability to last race after race. Fastener materials are available in 8740 Chrome Moly, ARP2000, and Custom Age 625+, each engineered for specific performance thresholds. In order to ensure optimum quality control, ARP controls all aspects of the manufacturing process entirely in-house — a discipline that has allowed it to build a reputation for &quot;zero defects&quot; quality throughout the industry.</p><p>Automotive Racing Products has achieved ISO 9001:2008 and AS9100 registration, certifications the company has maintained as a testament to its unwavering dedication to producing the highest quality fasteners available. ARP also operates an Aerospace Division and is one of the very few companies in the world fully licensed by the United States Government to manufacture MS-21250 fatigue-rated fasteners.</p><h3>Trusted by the World&apos;s Top Racing Programs</h3><p>ARP enjoys working relationships with professional engine builders and race teams across Formula 1, IndyCar, IMSA, NASCAR, NHRA, IHRA, Lucas Oil Late Model Dirt, and World of Outlaws — constant interaction that keeps ARP on the cutting edge of fastener technology. Whether you&apos;re building a weekend bracket racer or a full-time professional race engine, ARP has a solution engineered to hold things together under the most extreme conditions.</p><h3>ARP&apos;s Engine Fastener Lineup</h3><p>Today, ARP&apos;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. Among the most popular are <a href="/48-arp-engine-cylinder-head-bolt-set-10306">Engine Cylinder Head Bolt Sets</a>, <a href="/48-arp-engine-connecting-rod-bolt-5280">Engine Connecting Rod Bolts</a>, and complete <a href="/48-arp-engine-connecting-rod-5276">Engine Connecting Rods</a> — three categories that represent the critical fastening points where engine integrity is made or lost. ARP&apos;s High Performance series head bolt kits are rated at 170,000 psi — 15 percent stronger than Grade 8 fasteners — and are available with hex heads or reduced-wrenching 12-point heads that eliminate the need for valvetrain removal when re-torquing.</p><p>ARP stands behind its products indefinitely with respect to materials and workmanship, making every fastener a long-term investment in engine reliability rather than a consumable component.</p>

Part Number

135-2501
09/12/2036 6:40 AM
Sale Price

$24.64

In Stock (10+)

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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 135-2501 Harmonic Balancer Bolt Kit is specifically engineered for Chevrolet Big Block engines, providing superior clamping force and reliability compared to OEM fasteners. These high-strength bolts are manufactured from premium materials and heat-treated to deliver exceptional tensile strength, ensuring your harmonic balancer stays securely attached even under extreme racing conditions.

Key Specifications:

  • Thread Size: 1/2 inch - 20 TPI
  • Under Head Length: 1.550 inches
  • Socket Size: 5/8 inch hex
  • Application: Chevrolet Big Block V8 engines
  • Material: High-grade alloy steel with heat treatment
  • Finish: Black oxide for corrosion resistance

ARP fasteners are precision-manufactured to exacting tolerances and feature rolled threads that are significantly stronger than cut threads. This harmonic balancer bolt kit includes the necessary hardware to properly secure your damper, preventing potentially catastrophic engine damage from a loose or failed balancer. Each kit comes with ARP's ultra-torque assembly lubricant to ensure accurate torque readings and proper thread engagement.

Installation Note: Always follow ARP's recommended torque specifications and use the included assembly lubricant for optimal performance and fastener life.

Products specifications

Overall Diameter

1/2-20

Fastener Finish

Black oxide

Fastener Material

Chromemoly

Fastener Yield Strength (psi)

200,000 psi

Head Style

12-point

Quantity

Sold individually.

Socket

5/8

Thread Size

1/2-20 RH in.

UHL

1.55

Underhead Length (in)

1.550 in.

Washer Included

Yes

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