Manley Chevrolet Big Block Exhaust Valve Kit - 1.940in Head Dia. 5.422in O/A Length, 0.3415in Stem

If you're rebuilding the top end of a Chevrolet big block engine, especially one that sees high temperatures or demanding use, these Manley Severe Duty exhaust valves are a solid option. They're made from XH-428 material, which is specifically chosen for its strength at high temperatures, offering nearly double the tensile strength at 1500°F compared to other common exhaust valve materials like EV-8. This means they're built to handle the heat and stress of performance gasoline engines.

Manley put these valves through some serious testing, pushing them to 100 million cycles at 1400°F without failing. That's a remarkable fatigue life, especially when you consider that other valves in competitive tests failed after only 100,000 cycles. The design includes swirl-polished under-head areas and fully machined faces to help improve airflow into the cylinder and make combustion more efficient. Plus, they feature chrome stems and hard tips for added durability and longevity.

This kit includes exhaust valves with a 1.940-inch head diameter and an overall length of 5.422 inches, with a 0.3415-inch stem diameter. While these are exhaust valves, Manley also uses a unique NK-844 material for their intake valves, which has over four times the tensile strength of competing intake valve materials at 1000°F. Be sure to check the manufacturer's instructions for proper installation and any related components needed for your specific engine build.