oil pressure is predominantly a function of the pressure relief valve at the pump.
Oil viscosity, filters, and lines all have very little effect on hot
oil pressure,30-35 psi is plenty.... and that is the pressure you should be looking at....bad guage? maybe but not likely. also, don't worry too much about that distributor gear...it would take many thousands of miles to wear it out. most wear out from cam walk....not oil pressure.