BBC SD Exhaust Valve 1.940 11/32 6.400 OAL

The Manley BBC SD Exhaust Valve 1.940 11/32 6.400 OAL (MAN11583-1) is a severe-duty exhaust valve engineered for big-block Chevy performance and racing applications. This stainless steel component delivers the durability and precision needed in high-horsepower, sustained-rpm environments where standard valves fail. With a 1.940-inch head diameter and 0.342-inch valve stem, this valve is built to withstand extreme combustion pressures and extended operating cycles.

Manley's severe-duty construction means thicker, stronger material and tighter tolerances than OEM or street performance valves. The 6.400-inch overall length and precise 11/32-inch stem diameter ensure proper fit and sealing in BBC cylinder heads. Stainless steel construction resists corrosion and erosion from high-temperature exhaust gas flow, critical in forced-induction or high-boost applications. The valve's geometry and metallurgy are optimized for repeatability across thousands of heat cycles—essential for engines seeing consistent dyno pulls, competition use, or prolonged high-load operation.

This exhaust valve is specified for serious BBC builds: racing engines, marine performance platforms, and high-displacement street applications requiring reliability beyond stock parameters. Each valve is individually manufactured to Manley's exacting standards. Builders and engine shops trust Manley valves to hold boost, flow consistently, and resist thermal shock and scuffing—factors that separate finishes from DNFs in competitive or demanding duty cycles.

Proper valve selection is critical to big-block Chevy performance. The BBC SD Exhaust Valve 1.940 fits standard big-block Chevy port sizes and works with OEM or aftermarket cylinder head castings. Consult port size and stem diameter specifications for your specific BBC head before ordering. Sold individually; most builds require a full set of matched intake and exhaust valves, plus respective springs and retainers.