383N - 383M Series Brass Ball Valve, Ports, Black Handle

450 PSI is actually the rated maximum for this valve, so running at that pressure puts you right at the ceiling. For a system that sits at or near that level on a regular basis, you'd want to keep an eye on it over time, but it's built to handle that load. The brass body, ball, and stem are solid for pneumatic service, and the PTFE seats and Buna-N seal are what's doing the sealing work under pressure. As long as your system temps stay under 200 degrees F, you're within spec.