What makes Manley's NK-844 intake valve material special?

Manley states that their NK-844 material offers over four times the ultimate tensile strength of other leading intake valve materials at 1000°F. This means the valves are more resistant to stretching and deforming under high heat and pressure.

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

The swirl polishing helps to create a smoother path for the air-fuel mixture entering the combustion chamber. This can lead to improved airflow and more efficient combustion.

Are these valves sold individually or as a set?

This product is a set of eight intake valves, which is the standard quantity needed for a V8 engine.

Specifications

Brand: Manley Performance
Part #: 11530-8
UPC: 807298049663

Manley Chevrolet Big Block Severe Duty/Pro Flo 5.325in O/A Length Intake Valves (Set of 8)

Name: Manley Chevrolet Big Block Severe Duty/Pro Flo 5.325in O/A Length Intake Valves (Set of 8)
Brand: Manley Performance
SKU: manley-performance-manley-chevrolet-big-block-severe-duty-pro-flo-5-325in-o-a-le-t14-513723
Price: 361.47 USD
Availability: BackOrder

$361.47

On Backorder

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Manley Chevrolet Big Block Severe Duty/Pro Flo 5.325in O/A Length Intake Valves (Set of 8). Built with NK-844 material for high-temp gasoline engines.

Key Features

Set of 8 intake valves for Chevrolet Big Block engines.
Constructed from NK-844 material, known for high tensile strength at elevated temperatures.
Features chrome stems and hard tips for improved durability and longevity.
Swirl-polished under-head areas and fully machined combustion faces optimize airflow and combustion.
Designed for high-temperature gasoline engines.
Tested to endure up to 100 million cycles, offering exceptional fatigue life.

These are 5.325 inch overall length intake valves designed for Chevrolet Big Block engines. Please verify fitment with your specific engine build and cylinder head requirements.

⚠️ 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

When you're rebuilding the top end of a Chevrolet Big Block engine, especially one that sees hard use or high temperatures, you need intake valves that can handle the stress. These Manley Severe Duty/Pro Flo intake valves are built for just that scenario. They are made from NK-844 material, which Manley states has over four times the ultimate tensile strength of other leading intake valve materials at 1000°F, meaning they're designed to resist stretching and deformation under extreme heat and pressure.

Beyond the material, these valves feature chrome stems and hard tips for added durability, helping them stand up to repeated seating and unseating. The under-head areas are swirl-polished to help guide airflow smoothly into the combustion chamber, and the faces are fully machined for optimal combustion efficiency. Manley's testing shows their Severe Duty valves can endure up to 100 million cycles, a notable improvement over competitors that fail much sooner, indicating a much longer service life for your engine.

This set includes eight intake valves, enough for a standard V8 engine. If you're pushing your big block hard, these valves are a solid option to ensure reliable performance.