MERCURY 12558059 Gm Vortec Engine Cylinder Head 5.0

( Manufacturer Part Number: 12558059 ), ( Part Type: Engine Cylinder Head ), ( Country/region Of Manufacture: United States )

Review MERCURY 5.0 Gm Vortec Engine Cylinder Head fits MERCRUISER EFI MARINE 305 1998

The Mercury 12558059 cylinder head is specifically designed for the 98 Mercruiser 5.0 EFI 305 GM Vortec marine engine. This high-performance cylinder head is engineered to deliver superior power output and excellent thermal efficiency.

The head is constructed from aluminum alloy, which is lightweight yet strong and provides excellent heat dissipation properties. It features a four-valve design per cylinder with a compact combustion chamber that optimizes fuel-air mixture for maximum power. The combustion chamber is equipped with a wedge-shaped piston design that enhances compression and power output.

The cylinder head comes with fully machined and balanced ports for optimal airflow and efficient fuel injection. It also includes new spark plug locations and a revised ignition system for better combustion efficiency and improved engine performance.

The head is also equipped with a new cooling system design that includes larger coolant passages and improved water jackets to provide better cooling performance. The cooling system is designed to keep the engine running at optimal temperatures, even in high-stress conditions.

Additionally, the cylinder head features a redesigned valve train system with roller rocker arms and hydraulic lifters that provide smooth operation and reduced maintenance requirements. The valves are made from high-strength steel and are designed to provide excellent durability and long-lasting performance.

Overall, the Mercury 12558059 cylinder head is a high-performance upgrade for the 98 Mercruiser 5.0 EFI 305 GM Vortec marine engine. It delivers superior power output, excellent thermal efficiency, and improved cooling performance, making it an excellent choice for enthusiasts looking to maximize the performance of their marine engine.

Mercury 12558059 5.0 EFI 305 GM Vortec Marine Engine Cylinder Head: Pros, Cons, and Conclusion

The Mercury 12558059 cylinder head is a component of the 5.0 EFI 305 GM Vortec marine engine. This engine is known for its reliability and power, making it a popular choice for boaters. In this analysis, we'll discuss the advantages and disadvantages of purchasing this specific cylinder head.

1. Durability: The Mercury 12558059 cylinder head is made of high-quality materials, ensuring long-lasting performance. It can withstand the harsh marine environment, which is essential for boat engines.

2. Improved Performance: This cylinder head is designed to provide better fuel efficiency and power output compared to older models. It features improved combustion chamber design, which results in a more efficient burning process.

3. Easy Installation: The cylinder head is relatively easy to install, and it comes with all necessary gaskets and hardware. This can save time and money for boat owners who prefer to do the installation themselves.

1. Cost: The Mercury 12558059 cylinder head is a premium component, and it comes with a premium price tag. It may be more expensive than some aftermarket alternatives, making it a significant investment for some boat owners.

2. Availability: Due to its popularity, the Mercury 12558059 cylinder head can be challenging to find in stock at local marine parts stores. This may require boat owners to order it online, which can add extra time to the repair or upgrade process.

The Mercury 12558059 cylinder head offers several advantages, such as improved durability, performance, and easy installation. However, it also comes with some disadvantages, like its high cost and limited availability. For boat owners who prioritize reliability, efficiency, and power, this cylinder head is an excellent investment. However, for those on a tight budget or with limited access to marine parts stores, it might be worth considering alternative options.

If you're in the market for a new cylinder head for your 5.0 EFI 305 GM Vortec marine engine and are willing to invest in a high-quality component, the Mercury 12558059 cylinder head is an excellent choice. However, if you're looking for a more cost-effective alternative, consider exploring aftermarket options from reputable manufacturers. Be sure to research the specifications and compatibility before making a purchase.

Details:

Thanks -Mike. What you see in the pictures is what get. Condition: Good used condition. Please look at all pictures and read entire before buying.

Mounting hardware is only included if it shown in the pictures. I will do my best to resolve the issue. Shelf 25-14-6-A. Look at pictures closely and ask any questions, I try to describe parts as best can.

Part was removed from a 1998 Mercruiser 5.0 EFI Marine engine.

part #: 12558059 prices

• $242.34-$899.99

specifications intengster:

• for models: Efi, Marine, 305, Mercruiser
• for makes: Mercury
• for years: 1998
• mpn: 12558059
• part type: Engine Cylinder Head
• country/region of manufacture: United States

payments intengster:

• wallet: Google-pay
• other
• credit card: Mastercard

returns intengster:

• paid by: Buyer
• policy: Returns Accepted
• time: 30 Days

general intengster:

• Boat Parts > Sterndrive Motors Components > Internal Engine Parts
• condition: Used

seller intengster:

• # reviews: 103764
• rating: 99.1%
• city: Huron, Ohio

shipping intengster:

• type: Calculated
• service: FedEx Ground or FedEx Home Delivery, UPS Ground, FedEx 2Day
• class: Standard, Expedited
• carrier: FedEx, UPS
• transit: 3-7 Days
• cost: $100.82

offer intengster:

• started: March 25, 2025
• availability: In Stock
• options: Ship-to-home
• sold: 0
• quantity: 2

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