Manley Chevrolet Big Block Exhaust Valve Kit - 1.940in Head Dia. 6.400in O/A Length, 0.3415in Stem

Starting with XH-428 material for the exhaust valves, Manley Performance has created a kit designed for serious engine builds. This material offers nearly double the ultimate tensile strength at 1500°F compared to other common exhaust valve materials like EV-8, making these valves exceptionally strong for high-temperature gasoline engines. Each valve measures 1.940 inches across the head and has an overall length of 6.400 inches, with a 0.3415-inch stem diameter, fitting many Chevrolet big block applications.

These aren't just strong valves; they're built to last through extreme conditions. Manley's Severe Duty valves have undergone rigorous fatigue testing, enduring up to 100 million cycles at 40,000 psi and 1400°F. This is a notable improvement over competitor valves that often fail after only 100,000 cycles. The design includes swirl-polished under-head areas and fully machined combustion faces to help improve airflow and combustion efficiency, while chrome stems and hard tips add to their durability and longevity.

If you're rebuilding a high-performance or racing engine, these valves are a solid option. They are designed to handle the stresses of demanding operation, offering improved fatigue life and strength at high temperatures.