Pair GM Chevrolet 5.0L 305 Mercruiser Cylinder Heads – Casting Numbers 059 and 520 | 12552520 12558059 W/ Head Gasket Set and Bolts, Water Pump & Timing Set

Enhance your engine’s performance with the GM 5.0L 305 Cylinder Heads, featuring Casting Numbers #059 and #520. This complete set includes fully assembled cylinder heads, a head gasket set, bolts, water pump, and timing set, designed to meet or exceed OEM specifications for a perfect fit and reliable performance in marine environments. Built to withstand high heat and moisture, this set ensures a quick, hassle-free installation for your GM 5.0L 305 engine.

Key Features of GM Chevrolet 5.0L 305 Cylinder Heads

• Vehicle Compatibility: Perfect for GM Chevrolet 5.0L 305 and Mercruiser marine engines.
• Casting Numbers #059 & #520 for OEM Fit: Ensures a seamless fit and reliable performance.
• Complete Set for Easy Installation: Includes head gasket set, bolts, water pump, and timing set, making installation a breeze.
• Fully Assembled with Valves and Springs: Save time and effort with pre-assembled parts.
• Engineered for Marine Use: Built for high heat resistance and durability, ideal for marine applications.
• Perfect for Engine Rebuilds & Performance Upgrades: Enhances engine power and efficiency.

Applications for GM 5.0L 305 Cylinder Heads

• GM Chevrolet 5.0L 305 engine
• Mercruiser marine engines

Whether you’re performing routine maintenance, engine rebuilds, or performance upgrades, these cylinder heads offer reliable power and long-lasting durability. Designed for harsh marine conditions, they will ensure your engine performs at its best, wherever your adventures take you. No core return required.

Heavy Duty Parts Company – Quality You Can Trust

At Heavy Duty Parts Company, we take quality seriously. We thoroughly clean, inspect, and pressure test each cylinder head to ensure it meets the highest standards. Our state-of-the-art equipment is used for all seat and guide work, resurfacing, and vacuum testing. Whether you’re replacing a worn cylinder head or upgrading for enhanced performance, our cylinder heads exceed OEM standards, ensuring reliability and efficiency.

Warranty Information:

• Coverage: Heavy Duty Parts Company provides a two-year unlimited mileage parts warranty. A warranty card will be included with your invoice.
• Terms: By purchasing the cylinder head, you agree to the following warranty terms:
  • Keep the heat tab intact and unaltered.
  • Include a copy of the invoice and a Return Authorization number for returns.
  • The warranty covers parts only; labor and incidental costs are not covered.
  • The warranty does not cover damage caused by improper installation, overheating, abuse, or neglect.

Order Your New GM 5.0L 305 Cylinder Heads Now!

Ready to upgrade your vehicle? Order your premium New GM 5.0L 305 Cylinder Heads today and experience enhanced performance and reliability.

For questions or assistance, please contact our customer service team by email at sales@heavydutypartscompany.com.

Heavy Duty Parts Company – Core Returns Policy

At Heavy Duty Parts Company, core returns are essential to our ability to provide high-quality, cost-effective cylinder heads to our customers. These returned cores supply essential components, such as keepers, springs, and retainers, which are critical to engine performance.

No Core Charge – Just Send It Back!

Unlike other companies, we do not charge a core fee upfront. Instead, we rely on our customers to return their used cores to keep our supply chain running smoothly.

Why Core Returns Matter

• Many small but essential parts from cores are reused to maintain OEM-quality cylinder heads.
• Returning cores keeps prices competitive by reducing the need for costly new components.
• It supports sustainability by minimizing waste and conserving resources.

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!

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