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ARP 247-4204 Custom Age 625+ Cylinder Head Stud Kit 12-Point

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

247-4204
09/12/2036 4:31 AM
Sale Price

$1,232.98

3 left at this price

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Usually delivered within 2 days

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Live-in-stock inventory

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Fitment guaranteed

Fitment guaranteed

Product Details

The ARP 247-4204 Custom Age 625+ cylinder head stud kit represents the pinnacle of fastener technology for high-performance and racing engines. Engineered with ARP's proprietary Custom Age 625+ material, these studs deliver exceptional strength and reliability that professional engine builders demand for competition powerplants.

Premium Materials and Heat Treatment:

Each stud is manufactured from premium grade 8740 chrome moly steel alloy, rated superior to aircraft quality materials. ARP's precision heat treatment process involves placing studs vertically in special racks and treating them to achieve 200,000 psi tensile strength. This vertical rack method ensures complete and uniform heat penetration throughout each fastener, resulting in consistent mechanical properties that basket-treated fasteners cannot match.

Precision Manufacturing Process:

  • Centerless ground after heat treatment for exceptional concentricity and straightness
  • Thread rolling performed after heat treatment for approximately 1000% better fatigue strength
  • 12-point head design for precise torque application
  • Undercut shorter studs equalize stretch for consistent clamping force
  • Cold-forged construction ensures molecular integrity

Performance Advantages:

The precision manufacturing ensures that cylinder heads and gaskets align perfectly during assembly, eliminating the fitment issues common with lower-quality fasteners. The undercut design on shorter studs compensates for head gasket compression, providing more uniform clamping force across the entire head surface. This helps prevent head gasket failures and ensures optimal engine sealing under extreme conditions.

Why Studs vs Bolts:

Head studs offer significant advantages over bolts for performance applications. Studs install finger-tight in a relaxed state, then stretch only along the vertical axis when torqued. Bolts, by contrast, experience both torsional and tensile loads simultaneously during installation, resulting in less accurate and consistent clamping force. Studs also simplify engine assembly and disassembly, particularly important for racing engines requiring frequent service.

Each kit includes hardened, parallel-ground washers to ensure even load distribution and accurate torque readings. Every stud is marked with the ARP stamp as assurance of quality and authenticity. Note that cylinder heads must be re-torqued after initial engine run-in to compensate for head gasket compression.

Products specifications

Cut to Fit

No

Fastener Finish

Black oxide

Fastener Material

Custom age 625

Fastener Style

Stud

Head Style

12-point

Notes

Fits 24-valve engines.

Quantity

Sold as a kit.

Washers Included

Yes

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