What material are these exhaust valves made from and why is it important?

These Manley exhaust valves are made from XH-428 material. This material is chosen for its exceptional strength at high temperatures, offering significantly higher tensile strength compared to common exhaust valve materials like EV-8, which is crucial for performance engines.

What kind of testing have these valves undergone?

Manley has subjected these valves to rigorous fatigue testing, simulating extreme operating conditions. They have endured up to 100 million cycles at high pressure and temperature, demonstrating a much greater resistance to failure than competing valves.

Are these valves suitable for a street-driven vehicle or only for racing?

While built with severe duty and racing in mind, their improved durability and fatigue life make them a strong option for any high-performance gasoline engine, including those in street-driven vehicles that are pushed hard. They are designed for high-temperature gasoline engines.

Specifications

Brand: Manley Performance
Part #: 11677-8
UPC: 807298062792

Manley Chevy LS-6 Head Small Block Severe Duty/Pro Flo Exhaust Valves (Set of 8)

Name: Manley Chevy LS-6 Head Small Block Severe Duty/Pro Flo Exhaust Valves (Set of 8)
Brand: Manley Performance
SKU: manley-performance-manley-chevy-ls-6-head-small-block-severe-duty-pro-flo-exhaus-t14-299519
Price: 349.40 USD
Availability: BackOrder

$349.40

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Manley Chevy LS-6 Head Small Block Severe Duty/Pro Flo Exhaust Valves (Set of 8). Built for high-temp gasoline engines with exceptional fatigue life.

Key Features

Set of 8 Manley Severe Duty/Pro Flo exhaust valves for Chevy LS-6 small block engines.
Constructed from XH-428 material, offering exceptional strength at high temperatures.
Tested to withstand up to 100 million cycles at 40,000 psi and 1400°F for superior fatigue life.
Designed for high-temperature gasoline engines, providing improved durability and longevity.
Features chrome stems and hard tips for enhanced wear resistance.
Swirl polished under head areas and fully machined combustion faces improve airflow and combustion efficiency.

These valves are specifically designed for Chevy LS-6 small block engines. Always consult manufacturer fitment data to confirm compatibility with your specific engine build.

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About this part

Product Details

If you're building a high-performance Chevy LS-6 small block engine, these Manley Severe Duty/Pro Flo exhaust valves are a solid choice. They're made from XH-428 material, which is known for its strength at high temperatures, offering nearly double the tensile strength of common EV-8 material at 1500°F. This means they can handle the intense heat and stress inside a performance gasoline engine much better than standard valves.

Manley put these valves through some serious testing. In fatigue tests simulating extreme conditions, including valve bounce, these exhaust valves endured up to 100 million cycles at 40,000 psi and 1400°F. For comparison, other valves failed after only 100,000 cycles, showing these Manley valves have a much longer lifespan under demanding use. 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.

This set includes eight exhaust valves, each with a 1.600-inch head diameter and a .3136-inch stem diameter, with an overall length of 4.923 inches. They are designed to fit right into your LS-6 cylinder heads, making them a direct upgrade for your performance build.