What is "normal" oil pressure on a PCM 454? My boat has 1250 hours, and my gauge reads just about 20psi when at normal operating temp at idle, and 45-50 at WOT. The oil pressure dummy light and alarm will chirp at me coming back to idle. Sometimes on solid at idle, if it's warmer and pressure settles barely under 20 at 500rpm. Oil is already a little heavier Rotella 15w40.

This all seem a little low to me, and I had a buddy onboard that has a Mercruiser 454 based engine that run nearly double those numbers all the time. But his engine is a WAY different beast - the Mercury "Blue" 500 Bulldog in a Fountain...

I guess first step is to verify these numbers with a mechanical gauge, but what should i really be expecting?