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

These valves are made from XH-428 material, which Manley states offers significantly higher tensile strength at high temperatures compared to other common exhaust valve materials. This is crucial for handling the extreme heat and stress found in high-performance gasoline engines.

How do these valves compare to competitor valves in terms of durability?

Manley's testing indicates these Severe Duty valves endured up to 100 million cycles under severe conditions, which is substantially longer than competitor valves that failed after only 100,000 cycles. This suggests a much greater fatigue life.

What are the specific dimensions of these valves?

Each exhaust valve has a head diameter of 1.575 inches, a stem diameter of .3136 inches, and an overall length of 4.923 inches.

Specifications

Brand: Manley Performance
Part #: 11675-8
UPC: 807298062952

Manley Chevy LS-1/LS-2 Small Block 1.575 Pro Flo Severe Duty Exhaust Valves (Set of 8)

Name: Manley Chevy LS-1/LS-2 Small Block 1.575 Pro Flo Severe Duty Exhaust Valves (Set of 8)
Brand: Manley Performance
SKU: manley-performance-manley-chevy-ls-1-ls-2-small-block-1-575-pro-flo-severe-duty--t14-420063
Price: 349.40 USD
Availability: InStock

$349.40

Only 1 left in stock

Manley Chevy LS-1/LS-2 Small Block 1.575 Pro Flo Severe Duty Exhaust Valves (Set of 8). Built for high-temp gasoline engines with XH-428 material for extreme durability.

Key Features

Fits Chevy LS-1 and LS-2 small block engines.
Set includes 8 exhaust valves.
Constructed from XH-428 material for high-temperature strength.
Features chrome stems and hard tips for enhanced durability.
Swirl polished under head areas and fully machined combustion faces improve airflow.
Tested to withstand up to 100 million cycles at 40,000 psi and 1400°F.

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About this part

Product Details

Manley Performance is well-known for making strong internal engine components. These Pro Flo Severe Duty exhaust valves are a prime example, built specifically for Chevy LS-1 and LS-2 small block engines. If you're rebuilding the top end of your LS engine and need valves that can handle serious heat and stress, these are a solid option. They are designed to keep performing reliably in high-temperature gasoline applications.

These exhaust valves are crafted from XH-428 material, which Manley states has nearly double the ultimate tensile strength at 1500°F compared to other common exhaust valve materials like EV-8. They've also undergone rigorous fatigue testing, enduring up to 100 million cycles at 40,000 psi and 1400°F, far outlasting competitor valves that failed much sooner. The valves feature chrome stems and hard tips for added wear resistance, and the under-head areas are swirl polished while the combustion faces are fully machined to help improve airflow and combustion efficiency.

This set includes eight exhaust valves, each with a 1.575-inch head diameter and a .3136-inch stem diameter, with an overall length of 4.923 inches. They are a direct fit for the specified LS engines, and while they are built for extreme conditions, they are designed to install like standard valves. Always refer to your engine's service manual for specific installation procedures.