I thought this might interesting during the current cold snap.
I started my 2008 Chev 6.0 LS engine at -4 F and got around 20 psi indicated on the pressure gage. Once fully warm at 200 F on the water temp gage, it was idling at just under 40 psi. The oil is Pennzoil Platinum Euro 5w40. The oil pressure gage is high up on the engine and monitors the oil pressure after it goes through the filter and climbs up the oil galleys to the top of the engine.
I started my 2008 Chev 6.0 LS engine at -4 F and got around 20 psi indicated on the pressure gage. Once fully warm at 200 F on the water temp gage, it was idling at just under 40 psi. The oil is Pennzoil Platinum Euro 5w40. The oil pressure gage is high up on the engine and monitors the oil pressure after it goes through the filter and climbs up the oil galleys to the top of the engine.