Oil Pressure
10 lbs per 1000 rpm is pretty safe, and a higher viscosity oil like 20/50 would probobly raise that hot pressure a little, but also take more power to pump. I work on some old 2 stroke diesels that only have 3lbs hot idle pressure with straight 40wt oil! They run a long tome too, and the bearings look like new when you overhaul them. Go figure!