Manley 11398H-8 Race Series Stainless Steel Engine Valves - 8-Pack

Manley Performance has been manufacturing premium stainless steel valves for over 40 years, setting the industry standard for quality, durability, and performance. The Manley 11398H-8 Race Series Valves are engineered for domestic performance applications including Chevy LS, Ford Modular, and Chrysler Small Block HEMI platforms, delivering exceptional flow and strength in even the most demanding environments.

These valves are built using Manley's proprietary Race Series stainless steel alloy, chosen for its superior hot hardness and high-temperature strength. Each valve is manufactured to exacting tolerances and features a fully finished profile that sets them apart from the competition.

Key Features:

• Chrome-plated stems for durability and reduced friction
• Swirl-polished under-heads to promote airflow and reduce carbon buildup
• Fully hardened tips for long-term wear resistance under high spring pressures
• Completely machined combustion faces for precise sealing and optimal combustion efficiency
• Closely controlled margin heights ensuring consistent performance across all cylinders
• Exact stem-to-seat concentricity for superior sealing and reduced valve float
• Pro-Flo design on intake valves — reduced stem diameter in the fillet area for increased airflow and reduced valve weight (applied to LS and HEMI applications)
• Extremealloy exhaust material available in select applications (e.g., Ford Modular 4.6L and 5.4L 3-valve) for extreme boost and elevated exhaust gas temperatures

Manley Race Series valves are suitable for a wide range of performance builds, from mild street performance engines to 1,000+ horsepower purpose-built race engines. Manley was among the first manufacturers to offer L-92 profile valves and continues to lead the industry with hollow stem LS valves designed for maximum weight savings and performance.