Agree a 350hp 327 is not stock, and a 4door 300hp model would have been a little rare from my memory. Stock and in good condition you would be looking at oil pressure in the 45 to 50psig range cold, and it might drop off to 35 to 40psi at idle as it warms up. Cruising it would be at the upper numbers. After it got loosened up you often see hot idle OP of 20psi or a less, even down to low teens, bumping up to 30+ with rpm. Water temp is thermostat dependent, and they generally ran 180F stats stock, unless someone changed it to a 160F (or took it out!) chasing a heat problem. Like Geezer2 said, get a shroud, and a new stock core should do you fine, IMO.