I agree with the guys , gauges lie all the time,lol. If your valve guides are bad to give off a little smoke its likely the engine is in the same condition. First I would try a little heavier oil, synthetic is best IMO,since it looses less viscosity as the temp rise. I have 2 oil pressure gauges on my truck because I did not trust either, BUT, one is on top of the block and the other is on the bottom so naturally the give different readings. It does show me though how much pressure going in and how much pressure I am losing from the tired engine. I have 2 volt meters also and the are consistently different in voltage. What are your RPMs at idle? Heavier oil in a old engine has helped with some issues for me , just dont go to heavy.