Manley Chevrolet Big Block Exhaust Valve Kit - 1.600in Head Dia. 5.221in O/A Length, 0.3415in Stem

If you're rebuilding the top end of a Chevrolet big block engine, especially one that sees hard use or high temperatures, these Manley Severe Duty? exhaust valves are a solid option. They're made from XH-428 material, which Manley says has nearly double the tensile strength at 1500°F compared to other common exhaust valve materials like EV-8. This means they can handle the intense heat and stress inside the combustion chamber much better over the long haul.

Beyond the material, these valves are built for improved airflow and combustion. The under-head areas are swirl polished, and the combustion faces are fully machined. They also feature chrome stems and hard tips, which helps with durability and longevity in the valve guides. Manley's testing shows these valves can endure up to 100 million cycles under significant stress, which is a notable improvement over many other valves that might fail much sooner.

This kit includes exhaust valves with a 1.600-inch head diameter, a 5.221-inch overall length, and a 0.3415-inch stem diameter. Make sure these dimensions match your cylinder head and valve spring requirements for a proper fit.