4983298 | Cummins ISB 24V 6.7L Loaded Complete Reinforced New Cylinder Head | 3977221

Cummins ISB 24V 4983298 3977225 6.7L Loaded Complete Reinforced New Cylinder Head

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Fits: Cummins ISB 24V 6.7L engines
Displacement: 6.7L
Year Range: 2004-Present
Cylinders: 6

Parts Interchange:
3977225, 3977221, 4983298, 4983046

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Product Information

Introducing Heavy Duty Parts Company’s reinforced, redesigned, and reinvigorated brand new cylinder head for the industry’s workhorse, the Cummins ISB. Our cylinder head has been redesigned to address common flaws such as cylinder head cracking and premature valve train failure. This heavy-duty aftermarket casting is thicker internally in the crack-prone areas and contains a higher nickel content in the cast iron. The cylinder head comes fully assembled with valves, springs, retainers, valve locks, new high-temperature Viton valve stem seals, and standard size cam bearings. It is ready to install straight out of the box and built to outwork the rest with Heavy Duty Parts Company’s best!

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Overview

Upgrade your Cummins ISB 24V 6.7L engine with the top-of-the-line Cummins ISB 24V 3977225 Loaded Complete Reinforced New Cylinder Head. Specifically designed to enhance durability and performance, this cylinder head addresses common issues such as cracking and premature valve train failure, making it an ideal choice for heavy-duty applications from 2004 to present.

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Key Features

Reinforced Design:
Features a thicker casting in crack-prone areas and high nickel content in the cast iron, ensuring exceptional strength and longevity.

Premium Components:
Pre-loaded with high-quality valves, springs, retainers, valve locks, high-temperature Viton valve stem seals, and standard size cam bearings.

Ready to Install:
Fully assembled and ready for immediate installation, simplifying the replacement process and reducing downtime.

Compatibility:
Fits Cummins ISB 24V 6.7L engines (2004-Up) including both electronic and non-electronic variations.

Engine Type:
Diesel

Displacement:
6.7 liters.

Cylinders:
6

Core Return Required

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Benefits

Enhanced Durability:
The reinforced construction significantly reduces the likelihood of cracking and other common failures.

Improved Performance:
Optimized for better airflow and combustion, leading to increased engine efficiency and power.

Ease of Installation:
Pre-assembled with essential components, ensuring a hassle-free installation process and immediate performance benefits.

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Purchase Information

Maximize the performance and durability of your Cummins ISB engine with this robust and reliable cylinder head.

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Purchase and Shipping

We offer competitive pricing, and fast handling and shipping times. For more information on shipping times and costs, please visit our shipping policy page here: Shipping Policy.

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Additional Info

Check out Cummins Official Website here.

Core Return Required

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Heavy Duty Parts Company – Core Returns Policy

Effective December 17, 2025

At Heavy Duty Parts Company, core returns are essential to our ability to provide high-quality, cost-effective cylinder heads. Returned cores supply critical components—such as keepers, springs, and retainers—that are vital to proper engine performance and allow us to maintain OEM-level quality.

No Upfront Core Charge

Unlike many suppliers, we do not charge a core fee upfront. Instead, we rely on customers to return their used cores within the required timeframe.

Core Return Requirements

• Cores are due within 30 days of the purchase date

• If a core is not returned within 60 days, the product warranty is void

• Unreturned cores will be charged as follows:

  • Cylinder heads under $600: $200 per unreturned core

  • Cylinder heads $600 and above: $400 per unreturned core

Customers needing additional time may contact us to request an extension. Approved extensions will prevent core charges from being applied.

Core Return Process

Cylinder heads are shipped with prepaid core return labels included in packets attached to the outside of each box. If labels are missing, customers should contact us for replacements prior to returning the core.

Core Eligibility

Some cylinder heads do not require a core return. In certain cases, core requirements may be waived at our discretion.

Why Core Returns Matter

• Reused core components help maintain OEM-quality standards

• Core returns allow us to keep pricing competitive

• Recycling cores supports sustainability by reducing waste and conserving resources

This policy applies to all purchases made on or after December 17, 2025.

Send Back All Components

To ensure the quality and integrity of our remanufacturing process, we ask that you return all components that were originally included with your new cylinder head. This includes items such as:

• Rocker arms
• Camshafts (if applicable)
• Any other hardware that came with your purchase

Easy & Free Core Return Process

• Each purchase includes a prepaid core return label in a plastic sleeve on the box.
• Simply pack your core with all included components, attach the label, and drop it off with the carrier—no extra cost to you.
• Returned cores undergo inspection and recycling, ensuring maximum efficiency.

Customer Partnership & Sustainability

By returning your core and its components, you help maintain a reliable supply chain, ensuring we can continue offering top-quality products at the best prices. This process not only benefits your wallet but also contributes to a greener and more efficient automotive industry.

We appreciate your support in keeping our business and the industry running smoothly!