Manley Chevrolet Big Block Exhaust Valve Kit - 1.625in Head Dia. 4.921in O/A Length, 0.3415in Stem

Manley Performance is well-known for making strong internal engine components, especially for racing applications. This specific exhaust valve kit is designed for Chevrolet Big Block engines and uses their Severe Duty? XH-428 material, which is a standout choice for exhaust valves. It's built to handle the high temperatures and stresses found in performance gasoline engines.

These valves have undergone extensive fatigue testing, enduring up to 100 million cycles at 40,000 psi and 1400?F, which is a notable improvement over many other valves that might fail much sooner. The design includes chrome stems and hard tips for added durability, and the under-head areas are swirl polished while the combustion faces are fully machined. This attention to detail helps improve airflow and combustion efficiency within the engine. The XH-428 material itself offers nearly double the ultimate tensile strength at high temperatures compared to other common exhaust valve materials like EV-8.

This kit includes exhaust valves with a 1.625-inch head diameter and a 4.921-inch overall length, featuring a 0.3415-inch stem. If you're rebuilding the top end of your Chevrolet Big Block and need reliable exhaust valves that can withstand demanding conditions, these are a solid option.