Manley Chevrolet Big Block Exhaust Valve Kit - 1.940in Head Dia. 5.364in O/A Length, 0.3715in Stem

These Manley Severe Duty exhaust valves are made from XH-428 material, which has nearly double the ultimate tensile strength at 1500°F compared to other common exhaust valve materials like EV-8. This makes them a solid option for high-temperature gasoline engines, especially if you're rebuilding the top end of a Chevrolet Big Block. The valves measure 1.940 inches across the head and have an overall length of 5.364 inches, with a 0.3715-inch stem diameter, designed to fit right into your existing valve guides.

Manley put these valves through some serious testing, subjecting them to 40,000 psi at 1400°F and seeing them endure up to 100 million cycles. For comparison, other valves in the test failed after only 100,000 cycles. They also feature chrome stems and hard tips for added wear resistance, and the under-head areas are swirl-polished to help improve airflow into the combustion chamber.