I have been building engines for 40+ years (Harleys, GMC, Ford- to name a few) the Very Best way to insure that all internal moving parts "Wear in, seal, seat " so the finished engine will last 3-400,000 miles- is to use a "Break-in oil" that has proven itself time and time again. Royal Purple Break-in oil is made from a natural mineral oil, fortified with High amounts of Zinc, Phosphorus and Royal Purple's "secret sauce" that allows a correctly machined unit of parts, to polish themselves into near perfect fit and finish- it carries away the small particles as the engine wears in for the Best sealing rings, polished bearings, cushions the mass of moving steel unit, also allowing heat to be carried away as well- I had used this oil 3 years ago in a GMC K2500 with a 7.4 "Crate engine" from GM, changed the first oil at 100 miles, 2nd change at 400 miles, 3rd change at 500 miles more and every 500 miles until it had 2,500 miles total- now at 30,000 miles after running down the interstate at 80 MPH for 70 miles, I still have 80 pounds of oil pressure at the stop light - when I pulled the valve cover off, the contacted moving parts (rockers, pushrod ends) all are mirror polished- I'm rebuilding a 1986 Ford Ranger w/ 2.3 lt. engine- I'll follow the same intervals w/ this little engine - Thanks Amazon for the ability to buy this High Quality Break-in oil from the Backwoods of the Black Hills