First, you must realize that the stock oil pressure gauge, may or may not, be accurate. For the sake of discussion, let us
assume it is accurate.
The reason you have higher pressure is that you have gone from 10 weight oil to 30 weight oil. Both sets of readings sound just fine; factory literature indicates that 15 lbs is expected when warm and when driving. Factory literature also indicates you can use too heavy of an oil, especially in cold weather, and they caution against that. 30 weight oil this time of year in TX should be fine.
The other issue is detergent vs non-detergent. If the engine was rebuilt and used little since, it should not have much sludge, so I would tend to use the detergent oil with it's modern additives from now on.
Kent
