Manley 11686-1 Severe Duty Pro Flo Intake Valve 2.165 LS3 L92

The Manley 11686-1 is a high-performance Severe Duty Pro Flo intake valve engineered for Chevrolet LS3, L99, and L92 cylinder heads. This single valve features a 2.165-inch head diameter with a 0.3133-inch stem diameter and an overall length of 4.900 inches, making it the perfect replacement or upgrade for demanding performance applications.

Premium NK-844 Stainless Steel Construction:

Manley's Severe Duty valves are manufactured from proprietary NK-844 stainless steel material, which delivers over four times the ultimate tensile strength of competing intake valve materials at 1000°F. This superior alloy is specifically engineered for high-temperature gasoline engines, providing exceptional durability and longevity in extreme racing and performance conditions.

Key Features:

• 2.165-inch head diameter for optimal airflow
• 0.3133-inch stem diameter (5/16-inch)
• 4.900-inch overall length
• Pro Flo undercut stem design for improved flow characteristics
• Chrome plated stem for reduced friction and wear
• Hardened valve tip for extended valve train life
• Swirl polished under-head area for enhanced combustion efficiency
• Fully machined combustion face for precise sealing

Proven Performance:

Manley Severe Duty valves have undergone rigorous fatigue testing at 40,000 psi and 1400°F, enduring up to 100 million cycles—demonstrating 1000 times better fatigue life than competing valves. These valves are designed for bracket racing, drag racing, oval track, and high-performance street engines operating in demanding conditions.

Sold as a single valve. Ideal for engine builders seeking the ultimate in valve train reliability and performance for LS-based engines.