Hi Rick,
Don't worry, usually, a low
oil pressure means a good
oil flow! At least, you don't spend needlessly mechanical power to drive your
oil pump faster. Usually pressure switch (that monitore the red "too late" lamp) is adusted to swith on below 20 to 30 PSI.
It is a common practice for Nascar engine builders to adjust oil pressure at 10lbs per 1000rpm to be about 40 lbs at 4000rpm to 80 lbs at 8000 rpm (with external dry sump oil pump system you can easily adjust the oil pump rotation speed ratio). However, if you can listen some valve train noises, you can use an higher oil viscosity as propose Rick (W40 for winter looks OK). You have to check also the oil pressure gauge location. Oil pressure value may change according to the control point that can be before the main crank input or after the cam bearings. If you have an electrical oil pressure indicator, don't forget to check the oil pressure sender. Last issue, in case of doubt you can bring an oil sample to the chemist for analysis. He will be able to find any suspicious metallic particles.... if there is!