If this is a rebuilt engine, add some break-in oil and run the engine according to your camshaft manufacturer recommendations. A stock engine with little to no valve spring pressure will be much easier on the camshaft then strong race type spring, but it's still a good idea to use the correct oil. I run Mobil 1 5w20 in my 250, I change it every two or three years, which still isn't much mileage, but for the multiple short trips I make, I like the better oil.
