What makes these valves 'Severe Duty'?

Manley's Severe Duty valves are constructed from specialized materials like XH-428 for exhaust, offering significantly higher tensile strength at high temperatures compared to standard materials. They are also tested to withstand extreme cycle counts and stress levels.

What is the benefit of swirl-polished under-head areas?

The swirl-polished under-head areas are designed to improve airflow dynamics within the combustion chamber. This can contribute to more efficient combustion and potentially better engine performance.

Are these valves a direct replacement for stock valves?

Yes, these valves are designed with specific dimensions (1.600-inch head diameter, 0.3136-inch stem diameter, 5.215-inch length) to serve as direct replacements for the exhaust valves in Chevy LS3 and L99 engines with L92 heads.

Specifications

Brand: Manley Performance
Part #: 12355-8
UPC: 807298105932

Manley Chevy Small Block LS3/L99 (L92 Head) 1.6in Head Dia. Severe Duty Exhaust Valves (Set of 8)

Name: Manley Chevy Small Block LS3/L99 (L92 Head) 1.6in Head Dia. Severe Duty Exhaust Valves (Set of 8)
Brand: Manley Performance
SKU: manley-performance-manley-chevy-small-block-ls3-l99-l92-head-1-6in-head-dia-seve-t14-466407
Price: 349.40 USD
Availability: BackOrder

$349.40

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Manley Severe Duty exhaust valves for Chevy LS3/L99 (L92 Head) engines. Made from XH-428 material for extreme durability.

Key Features

Fits Chevy Small Block LS3 and L99 engines with L92 heads.
Set of 8 severe duty exhaust valves.
Exhaust valves are made from XH-428 material for high-temperature strength.
Head diameter is 1.600 inches.
Stem diameter is 0.3136 inches.
Overall length is 5.215 inches.

These valves are designed for Chevy Small Block LS3 and L99 engines with L92 heads. Please verify compatibility with your specific engine configuration.

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About this part

Product Details

Manley Performance is well-known for making strong engine components, and these Severe Duty? exhaust valves are a prime example. If you're working on a Chevy Small Block LS3 or L99 engine with L92 heads, these valves are built to handle the heat and stress of high-performance 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 competing 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 other valves that failed much sooner. The design includes swirl-polished under-head areas and fully machined combustion faces to help improve airflow and combustion efficiency. They also feature chrome stems and hard tips for added durability.

This set includes 8 exhaust valves, each with a 1.600-inch head diameter and a 0.3136-inch stem diameter, with an overall length of 5.215 inches. These are designed as direct replacements for your engine's exhaust valves.