What makes these valves 'Severe Duty'?

The 'Severe Duty' designation comes from the specialized NK-844 material used for intake valves, which offers significantly higher tensile strength at high temperatures. They've also undergone rigorous fatigue testing, enduring up to 100 million cycles compared to competitors failing much sooner.

What is the benefit of swirl-polished under-head areas?

Swirl polishing the area under the valve head helps to smooth the airflow as it enters the combustion chamber. This can contribute to improved combustion efficiency and overall engine performance.

Are these valves suitable for a stock engine rebuild?

While designed for demanding use, these well-built valves can certainly be used in a stock rebuild if you anticipate higher operating temperatures or want added durability. They are particularly beneficial if your engine build involves modifications that increase heat or stress.

Specifications

Brand: Manley Performance
Part #: 11590-8
UPC: 807298050829

Manley Big Block Ford 429-460 2.400in Diameter 5.725in Length Severe Duty Intake Valves (Set of 8)

Name: Manley Big Block Ford 429-460 2.400in Diameter 5.725in Length Severe Duty Intake Valves (Set of 8)
Brand: Manley Performance
SKU: manley-performance-manley-big-block-ford-429-460-2-400in-diameter-5-725in-length-t14-423194
Price: 361.47 USD
Availability: BackOrder

$361.47

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Manley Severe Duty Intake Valves for Big Block Ford 429-460. 2.400in diameter, 5.725in length. Built for high-temp gasoline engines.

Key Features

Set of 8 Severe Duty intake valves for Big Block Ford 429-460 engines.
Constructed from NK-844 material, chosen for its high tensile strength at elevated temperatures.
Intake valves measure 2.400 inches in diameter and 5.725 inches in length.
Features chrome stems and hard tips for improved durability and longevity.
Swirl-polished under head areas and fully machined combustion faces help optimize airflow.
Designed for high-temperature gasoline engines, offering improved fatigue life under stress.

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

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About this part

Product Details

These Manley Severe Duty intake valves are made from NK-844 material, a specialized alloy chosen for its exceptional strength at high temperatures. They measure 2.400 inches in diameter and 5.725 inches in length, designed specifically for Big Block Ford 429 and 460 engines. If you're rebuilding the top end of one of these classic Ford V8s, especially for performance applications, these valves are built to handle the stress.

Manley's NK-844 material for intake valves offers significantly higher tensile strength at elevated temperatures compared to common alternatives, meaning they're less likely to warp or fail under demanding conditions. The valves also feature chrome stems and hard tips for added durability, along with swirl-polished under-head areas and fully machined faces to help optimize airflow into the combustion chamber. These features work together to support efficient combustion and sustained performance.

This set includes eight intake valves, enough for a complete V8 engine. They are well-built for engines that run hot, whether from high compression, aggressive camshafts, or heavy-duty use.