Manley 11663B-4 Race Master 40mm Single Groove Exhaust Valves for VW Type IV

The Manley 11663B-4 Race Master exhaust valves are precision-engineered 40mm single-groove exhaust valves designed for Volkswagen Type IV air-cooled engines. Built to withstand the demands of high-performance street and race applications, these valves deliver reliable flow and durability in the most demanding thermal environments.

Key Features:

• XH-426 Stainless Steel Construction: Exhaust valves are forged from high-grade XH-426 stainless steel for superior heat resistance and long-term durability
• Chrome Stems & Hard Tips: Chrome-plated stems and hardened valve tips provide enhanced wear resistance and extended service life
• Swirl Polished Underhead: Swirl polished under-head areas and fully machined combustion faces optimize airflow and combustion efficiency
• Single Groove Design: Single keeper groove configuration (the "B" suffix designation) for compatibility with single-groove retainer systems
• Head Diameter: 40.0mm
• Stem Diameter: 0.313 in.
• Overall Length: 4.606 in.
• Stock Height: Drop-in replacement at OEM valve height

Manley Race Master valves are the preferred choice for bracket racing, oval track, and high-performance street engines operating under 8,000 RPM. The 11663B-4 is also a recommended option for exhaust valves in alcohol-fueled engine builds.