OK, on the driving tests.
1. Put on another oil pressure gauge and re-check
2. Brass shim stock may be at the local hardware store
3. One possible issue with higher pressure is blowing out oil filter gaskets. You are not quite there in my experience as it sounds like you are going no higher than 80 psi (glad you checked), but close. jimjimjimmy's experience is the concern: relief spring wrong or spring plug put in backwards or relief valve stuck in its bore. Higher weight oil and colder temps will make the pressure higher.