What makes Manley's XH-428 material special for exhaust valves?

The XH-428 material is unique to Manley and offers significantly higher tensile strength at high temperatures, nearly double that of common materials like EV-8. This allows the valves to withstand extreme heat and stress without deforming or failing.

How durable are these valves compared to others?

Manley's Severe Duty valves have undergone rigorous fatigue testing, enduring up to 100 million cycles at high stress and temperature levels. This is reported to be up to 1000 times longer than some competitor valves that failed much sooner.

Are these valves suitable for street use or just racing?

These valves are designed for high-temperature gasoline engines and have demonstrated extreme durability in testing. While built for demanding applications, their robust construction and improved airflow can benefit performance in various engine builds.

Specifications

Brand: Manley Performance
Part #: 12843-8

Manley Chevy Big Block Chevy 1.880in Severe Duty Exhaust Valves

Name: Manley Chevy Big Block Chevy 1.880in Severe Duty Exhaust Valves
Brand: Manley Performance
SKU: manley-performance-manley-chevy-big-block-chevy-1-880in-severe-duty-exhaust-valv-t14-553758
Price: 349.40 USD
Availability: BackOrder

$349.40

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Manley Chevy Big Block Chevy 1.880in Severe Duty Exhaust Valves. Built for high-temp gasoline engines with XH-428 material for extreme durability.

Key Features

Fits Big Block Chevy engines with 1.880 inch exhaust valve diameter.
Constructed from XH-428 material, offering exceptional strength at high temperatures.
Tested to endure up to 100 million cycles under extreme stress and heat.
Features chrome stems and hard tips for improved durability and longevity.
Swirl-polished under-head areas and machined combustion faces enhance airflow and combustion efficiency.
Designed for high-temperature gasoline engine 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

If you're rebuilding the top end of a high-temperature gasoline engine, especially a Big Block Chevy, you need exhaust valves that can handle the heat and stress. Manley's Severe Duty exhaust valves are made from XH-428 material, a unique alloy that offers nearly double the tensile strength at 1500°F compared to other common exhaust valve materials like EV-8. This means they're built to last under demanding conditions.

These valves have been put through some serious testing, enduring up to 100 million cycles in fatigue tests at 40,000 psi and 1400°F, which is a remarkable 1000 times longer than some competitor valves. They also feature chrome stems and hard tips for added wear resistance, and the under-head areas are swirl-polished to help improve airflow and combustion efficiency. The fully machined combustion faces also contribute to better performance.

With a 1.880-inch diameter, these valves are specifically designed for Big Block Chevy applications. If you're looking for a well-built exhaust valve that can stand up to extreme temperatures and high cycle counts, these Manley Severe Duty valves are a solid option.