Manley Chevrolet Small Block Exhaust Valve Kit - 1.600in Head Dia. 5.140in O/A Length, 0.3110in Stem

Starting with the XH-428 material for the exhaust valves, Manley Performance has developed a kit that stands up to serious heat and stress. These valves are designed for high-temperature gasoline engines, and the XH-428 alloy offers nearly double the ultimate tensile strength at 1500°F compared to other common exhaust valve materials like EV-8.

Beyond the material, these valves feature chrome stems and hard tips for added durability, helping them last longer in demanding conditions. The under-head areas are swirl polished, and the combustion faces are fully machined. This design work helps improve airflow into the cylinder and contributes to more efficient combustion. Manley's testing shows these valves can endure up to 100 million cycles at 40,000 psi and 1400°F, which is a notable improvement over many competing parts that might fail much sooner.

This kit includes eight exhaust valves, each measuring 1.600 inches across the head and 5.140 inches overall in length, with a 0.3110-inch stem diameter. They are a solid option for rebuilding or upgrading the top end of a Chevrolet small block engine.