LS3 S/D 1.590 Exhaust Valves

The MANLEY LS3 S/D 1.590 Exhaust Valves are purpose-built for high-performance LS-series engine applications demanding severe-duty reliability and sustained valve stability. This set of eight stainless steel exhaust valves is engineered for builders and enthusiasts who require OEM-compatible components with enhanced durability specifications. Whether you're assembling a street performance engine, a track-focused build, or a heavily modified LS platform, these valves deliver the thermal resistance and mechanical precision needed for demanding operating conditions.

Each valve features a 1.590-inch head diameter paired with a 0.314-inch valve stem and extends 4.923 inches in overall length, ensuring proper fitment across LS3, L99, and L92 engine variants. The stainless steel construction resists oxidation and thermal cycling fatigue, critical factors in exhaust environments where temperatures regularly exceed 1,200 degrees Fahrenheit. MANLEY's severe-duty classification indicates these valves meet enhanced material specifications and tighter tolerances compared to standard replacements, reducing valve recession and extending service intervals in high-RPM applications.

This complete eight-valve set fits GM LS-series Gen III and Gen IV engines, making it essential for full engine rebuilds or performance upgrades targeting maximum reliability. Installation requires proper valve seat cutting and spring rate verification to ensure correct geometry and seating pressure. Professional engine builders and serious enthusiasts recognize MANLEY valves as industry-standard components for engines destined for high-horsepower output or extended racing service. Verify head compatibility and consult OEM specifications before ordering to confirm fitment with your specific cylinder head casting.