What makes these valves 'Severe Duty'?

The 'Severe Duty' designation comes from their exceptional performance in rigorous fatigue testing. They endured up to 100 million cycles under high stress and temperature, far exceeding the lifespan of many competitor valves.

What material are the exhaust valves made from?

These exhaust valves are made from XH-428 material. Manley states this material offers nearly double the ultimate tensile strength at 1500?F compared to common EV-8 materials used by competitors.

Do these valves come with any installation hardware?

This product includes a set of 8 exhaust valves. Installation hardware such as valve springs, retainers, or seals are typically sold separately and should be checked for compatibility.

Specifications

Brand: Manley Performance
Part #: 11661-8
UPC: 807298051451

Manley Chevy LS-3/L-99 Small Block Severe Duty Exhaust Valves (Set of 8)

Name: Manley Chevy LS-3/L-99 Small Block Severe Duty Exhaust Valves (Set of 8)
Brand: Manley Performance
SKU: manley-performance-manley-chevy-ls-3-l-99-small-block-severe-duty-exhaust-valves-t14-281090
Price: 349.40 USD
Availability: BackOrder

$349.40

On Backorder

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

Manley Chevy LS-3/L-99 Small Block Severe Duty Exhaust Valves (Set of 8). Built for high-temp gasoline engines with superior fatigue life.

Key Features

Fits Chevy LS-3 and L-99 Small Block engines.
Set includes 8 exhaust valves.
Constructed from XH-428 material, known for high tensile strength at elevated temperatures.
Tested to withstand up to 100 million cycles under high stress and temperature.
Features chrome stems and hard tips for enhanced durability.
Swirl polished under head areas and machined combustion faces optimize airflow.

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About this part

Product Details

Manley Performance is well-known for making strong engine components for racing and high-performance applications. These Severe Duty? exhaust valves are a prime example of their commitment to building parts that can handle serious stress. If you're rebuilding the top end of your Chevy LS-3 or L-99 small block engine, these valves are designed to keep going under demanding conditions.

Crafted from XH-428 material, these exhaust valves are built for high-temperature gasoline engines. This material has nearly double the ultimate tensile strength at 1500?F compared to common EV-8 materials. They've been put through rigorous fatigue tests, enduring up to 100 million cycles at 40,000 psi and 1400?F, which is a notable improvement over many competitor parts that failed much sooner. The valves also feature chrome stems and hard tips for added durability, and the under-head areas are swirl polished with fully machined combustion faces to help improve airflow and combustion efficiency.

This set includes eight exhaust valves, each with a 1.590-inch head diameter and a 0.3136-inch stem diameter. They are designed as a direct replacement for your stock valves, making them a solid option for anyone looking to improve the reliability and performance of their engine.