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It's hard to believe no one has reviewed these guys yet. Very professional and detailed company it was a pleasure doing business with you. The answered the phone every time I called or answered every email in a timely manner! I will definitely use them for all my cylinder head needs moving forward. Thank again!

— Chris Burch

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Product was as described and packaged well! Communication throughout prosses was also great! I will definitely be using them in the future with other projects.

— Tommy Starogiannis

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Parts arrived as promised. Ported heads gave me that low end torque and high rev HP I was looking for! ...if only I did the cam at the same time.

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Best prices and customer service on Duramax LML heads out there. Shipped fast and very cool about how long it took to get the cores back.

— Dan

Cummins ISX / QSX Heavy-Duty Valve Set | 21-4N Martensitic & Austenitic Stainless (24pc)

Name: Cummins ISX / QSX Heavy-Duty Valve Set | 21-4N Martensitic & Austenitic Stainless (24pc)
SKU: CUMV1N
Availability: InStock

$379.00

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Additional Info

Cummins ISX / QSX Heavy-Duty Valve Set | 21-4N Martensitic & Austenitic Stainless (24pc) 📊

Stop praying for your engine to survive another haul and start installing the professional-grade solution for your Cummins ISX or QSX platform.

This is the definitive 24-piece valvetrain kit engineered for high-performance diesel endurance. Built using the sacred 21-4N High-Temp Stainless Steel, these valves are designed to resist “tuliping,” snapping, or burning up under the extreme EGTs and pressures of heavy-duty hauling.

🛠️ The Dual-Alloy Advantage

Intake Valves (Martensitic SS): Forged from high-grade Martensitic alloy to provide a rigid structural backbone. These are immune to the fatigue and corrosion that crush lesser “budget” components.
Exhaust Valves (Austenitic 21-4N): Designed to live in the furnace. These thrive in extreme heat, resisting oxidation and warping even when your turbocharger’s wake reaches peak temperatures.
Precision Ground Seats: Features 20° Intake and 45° Exhaust angles, precision-ground for a gas-tight, high-pressure seal that restores lost compression instantly.
Ultra-Tight Stem Tolerances: Held to .3789″ stem diameter specifications to eliminate guide slop and oil consumption upon installation.
Single-Groove Lock: Engineered for maximum security, ensuring the valves stay locked in place regardless of RPM or load.

📊 Technical Specifications

Condition: Brand New High-Performance
Quantity: 24-Piece Full Set (12 Intake, 12 Exhaust)
Material: 21-4N Martensitic & Austenitic Stainless Steel
Intake Dimensions: Head: 1.870″ | OAL: 8.503″ | Tip: .4669″
Exhaust Dimensions: Head: 1.790″ | OAL: 8.810″ | Tip: .7579″
Stem Diameter: .3789″
Groove Style: Single Groove
Engine Compatibility: Cummins ISX / QSX Platforms

💡 Machinist’s Pro Tip

Don’t put premium valves into worn-out guides. Always check your guide tolerances during assembly. To achieve “Top Dollar” performance, ensure your cylinder head preparation matches the elite quality of this 21-4N stainless steel kit. 🏎️

📦 Order Information & Warranty

Fast Fulfillment: We ship rapidly because a downed truck is a loss. Get your fleet back on the road with precision-engineered parts.
The Guarantee: Includes 90 Days of protection against manufacturing defects.
Expert Support: Talk to real machinists who know how to build a head. For assistance, call the line: 727-609-1700.

Dedicated to Customer Satisfaction

What sets us apart from the competition is our dedication to customer satisfaction. We strive to make your shopping experience as seamless and convenient as possible. Our user-friendly online platform allows you to browse our comprehensive inventory, compare products, and place orders with ease. With secure payment options and swift shipping, you can trust that your order will arrive promptly, minimizing downtime and maximizing productivity.

727-609-1700

sales@heavydutypartscompany.com