What makes these valves 'Severe Duty'?

The 'Severe Duty' designation comes from extensive fatigue testing. These valves have shown they can withstand up to 100 million cycles, far exceeding the lifespan of many competitor valves under similar stress conditions.

What material are these intake valves made from?

These intake valves are constructed from NK-844 material. Manley states this material offers significantly higher tensile strength at high temperatures compared to other common intake valve materials.

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

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

Specifications

Brand: Manley Performance
Part #: 11820-8
UPC: 807298053257

Manley Chevrolet 1.840 Dia Dish 5.140 O/A Length Severe Duty Intake Valves (Set of 8)

Name: Manley Chevrolet 1.840 Dia Dish 5.140 O/A Length Severe Duty Intake Valves (Set of 8)
Brand: Manley Performance
SKU: manley-performance-manley-chevrolet-1-840-dia-dish-5-140-o-a-length-severe-duty--t14-4379335
Price: 361.47 USD
Availability: BackOrder

$361.47

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Manley Chevrolet Severe Duty Intake Valves (Set of 8). Built for high-temp gasoline engines with improved fatigue life.

Key Features

This set includes 8 intake valves for Chevrolet engines.
Made from NK-844 material for high tensile strength at elevated temperatures.
Features chrome stems and hard tips for enhanced durability.
Swirl-polished under head areas and fully machined combustion faces improve airflow.
Underwent rigorous fatigue testing, enduring up to 100 million cycles.
Designed for high-temperature gasoline engines.

⚠️ 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

Manley Performance is well-known for making strong engine components, especially for racing applications. These Severe Duty? Intake Valves are a prime example of their commitment to building parts that can handle tough conditions. If you're rebuilding a high-temperature gasoline engine, these valves are designed to keep up with demanding use.

These intake valves are made from NK-844 material, which Manley states has over four times the ultimate tensile strength of competing materials at 1000°F. They also feature chrome stems and hard tips for added durability, and the under-head areas are swirl-polished to help improve airflow into the combustion chamber. The fully machined combustion faces also contribute to better airflow and combustion efficiency.

Manley has put these valves through rigorous fatigue testing, showing they can endure up to 100 million cycles under stress that would cause many other valves to fail much sooner. This level of fatigue resistance is notable for engines that experience valve bounce on the seat during operation. This set includes 8 intake valves.