What material are these intake valves made from?

These Manley intake valves are made from NK-844 material. This material is chosen for its high tensile strength at elevated temperatures, making it suitable for demanding engine applications.

What does '.250 longer' mean for these valves?

The '.250 longer' designation means these valves are a quarter of an inch longer than the standard factory intake valves for many Chevy Big Block engines. This is often necessary when using different cylinder heads or camshafts to ensure proper valve train geometry and lift.

Are these valves suitable for racing applications?

Yes, Manley designs these as 'Severe Duty' valves, indicating they are built to withstand higher stresses and temperatures commonly found in racing and high-performance gasoline engines. They have undergone rigorous fatigue testing.

Specifications

Brand: Manley Performance
Part #: 11854-8
UPC: 807298054094

Manley Chevy Big Block .250 Longer 11/32in Stem Dia Severe Duty Intake Valves (Set of 8)

Name: Manley Chevy Big Block .250 Longer 11/32in Stem Dia Severe Duty Intake Valves (Set of 8)
Brand: Manley Performance
SKU: manley-performance-manley-chevy-big-block-250-longer-11-32in-stem-dia-severe-dut-t14-4331914
Price: 349.40 USD
Availability: BackOrder

$349.40

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Manley Chevy Big Block .250 Longer 11/32in Stem Dia Severe Duty Intake Valves (Set of 8). Built for high-temp gasoline engines.

Key Features

Fits Chevy Big Block engines.
Set includes 8 intake valves.
Each valve is .250 inches longer than stock.
Features an 11/32 inch stem diameter.
Constructed from Manley's NK-844 material for high-temperature strength.
Swirl-polished under head areas and machined combustion faces improve airflow.

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About this part

Product Details

If you're rebuilding the top end of a Chevy Big Block engine, especially one that sees hard use, these Manley Severe Duty intake valves are a solid choice. They're built to handle the extra stress that comes with performance applications. Each valve is .250 inches longer than stock and features an 11/32 inch stem diameter, which is common for many Chevy Big Block applications.

Manley uses their NK-844 material for these intake valves, which they say has significantly higher tensile strength at high temperatures compared to other common intake valve materials. This means they're less likely to stretch or deform under the heat and pressure of combustion. The valves also feature swirl-polished under-head areas and machined combustion faces to help improve airflow into the cylinder, contributing to better combustion efficiency. Plus, the chrome stems and hard tips add to their durability, helping them last longer in demanding conditions.

This set includes eight intake valves, enough for a standard V8 engine. When you're putting together a high-performance engine, using well-built components like these valves can make a real difference in reliability and performance.