What material are these intake valves made from?

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

What makes these 'Severe Duty' valves different?

The 'Severe Duty' designation comes from rigorous fatigue testing Manley has performed. These valves have shown the ability to withstand a very high number of cycles, even under simulated harsh conditions like valve bounce, indicating improved longevity.

Are these valves suitable for all Big Block Chevy engines?

These valves are designed for Big Block Chevy engines and are particularly well-suited for high-temperature gasoline applications. It's always best to confirm specific engine compatibility based on your build's requirements.

Specifications

Brand: Manley Performance
Part #: 11520-8
UPC: 807298049441

Manley Big Block Chevy Stock 3/8in Stem Diameter Severe Duty Intake Valves (Set of 8)

Name: Manley Big Block Chevy Stock 3/8in Stem Diameter Severe Duty Intake Valves (Set of 8)
Brand: Manley Performance
SKU: manley-performance-manley-big-block-chevy-stock-3-8in-stem-diameter-severe-duty--t14-303968
Price: 349.40 USD
Availability: BackOrder

$349.40

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Manley Big Block Chevy Severe Duty Intake Valves (Set of 8). These well-built valves offer improved durability for high-temperature engines.

Key Features

This product is a set of 8 Manley Severe Duty intake valves.
Each valve has a stock 3/8-inch stem diameter.
Constructed from NK-844 material, known for its high tensile strength at elevated temperatures.
Features chrome stems and hard tips for improved durability.
Swirl-polished under-head areas and machined combustion faces aid airflow and combustion.
Designed for high-temperature gasoline engines, including Big Block Chevy applications.

⚠️ 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

This set includes eight Manley Severe Duty intake valves, each featuring a 3/8-inch stem diameter. These valves are specifically made for Big Block Chevy engines and are designed to handle the demands of high-temperature gasoline applications. They are built with NK-844 material for the intake side, which Manley states has over four times the ultimate tensile strength of competing materials at 1000°F. This makes them a solid option for engines that see a lot of heat.

Manley has put these valves through rigorous fatigue testing. In tests simulating valve bounce on the seat, which can apply extreme stress, these valves endured up to 100 million cycles. This is a notable improvement over competitor valves that failed much sooner, indicating a significant difference in fatigue life. The valves also feature chrome stems and hard tips for added durability, along with swirl-polished under-head areas and fully machined combustion faces to help optimize airflow and combustion efficiency.