What makes the XH-428 material special for exhaust valves?

The XH-428 material used for these exhaust valves offers significantly higher tensile strength at high temperatures compared to common alternatives. Manley states it has nearly double the strength at 1500°F, making it well-suited for demanding engine conditions.

How durable are these valves against fatigue?

Manley's Severe Duty valves have undergone extensive fatigue testing. They have demonstrated the ability to withstand up to 100 million cycles at 40,000 psi and 1400°F, indicating a very long service life under stress.

Are these valves suitable for standard street engines?

These valves are designed for high-temperature gasoline engines and are built with materials and testing geared towards performance and racing applications. While they can be used in street engines, their exceptional strength and durability are most beneficial in demanding or modified builds.

Manley Exhaust Valve Kit 1.725in 5.374in 0.3715in Stem 11835

Name: Manley Chevrolet Big Block Exhaust Valve Kit - 1.725in Head Dia. 5.374in O/A Length, 0.3715in Stem
Brand: Manley Performance
SKU: manley-performance-manley-chevrolet-big-block-exhaust-valve-kit-1-725in-head-dia-t14-879488
Price: 456.58 USD
Availability: BackOrder

Manley Chevrolet Big Block Exhaust Valve Kit - 1.725in Head Dia. 5.374in O/A Length, 0.3715in Stem

$456.58

On Backorder

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

Manley Chevrolet Big Block Exhaust Valve Kit - 1.725in Head Dia. 5.374in O/A Length, 0.3715in Stem. Built for high-temp gasoline engines with exceptional fatigue life.

Key Features

Fits Chevrolet Big Block engines.
Exhaust valves are made from XH-428 material for high-temperature strength.
Features a 1.725-inch head diameter.
Overall length is 5.374 inches.
Stem diameter measures 0.3715 inches.
Chrome stems and hard tips enhance durability.

⚠️ 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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Product Details

Manley Performance is well-known for making strong internal engine components for racing and high-performance applications. This exhaust valve kit is a prime example, featuring valves specifically designed for Chevrolet Big Block engines. These aren't just any valves; they are built from XH-428 material, which Manley states offers nearly double the ultimate tensile strength at 1500°F compared to other common exhaust valve materials like EV-8. This means they can handle the extreme heat and stress found in high-temperature gasoline engines.

You can expect improved airflow and combustion efficiency thanks to the swirl-polished under-head areas and fully machined combustion faces. The valves also feature chrome stems and hard tips, adding to their durability and longevity. Manley has put these valves through rigorous fatigue testing, showing they can endure up to 100 million cycles at 40,000 psi and 1400°F, which is a notable improvement over many competitor parts that might fail much sooner. This makes them a solid option for demanding engine builds where reliability under stress is critical.

This kit includes exhaust valves with a 1.725-inch head diameter, a 5.374-inch overall length, and a 0.3715-inch stem diameter. If you're rebuilding the top end of a high-performance Chevrolet Big Block, these valves are built to withstand the heat and pressure.