Manley Chevrolet Big Block Exhaust Valve Kit - 1.900in Head Dia. 5.522in 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, you'll want to consider these Severe Duty? exhaust valves from Manley Performance. These aren't your average valves; they're built with XH-428 material, which Manley claims 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 a performance gasoline engine much better.

Manley put these valves through some serious testing, subjecting them to 40,000 psi and 1400°F. They held up for an incredible 100 million cycles, which is a thousand times longer than some competitor valves that failed after only 100,000 cycles. The valves also feature chrome stems and hard tips for added durability, and the under-head areas are swirl-polished with fully machined faces to help improve airflow and combustion efficiency. The specific dimensions are a 1.900-inch head diameter, 5.522-inch overall length, and a 0.3415-inch stem diameter.