Remember when the engine is very first started, you should run it at about 2000 RPM to break in the camshafts, this is a relatively low RPM with relatively high oil pressure. Do this for about 20 minutes. Running organic (IE not synthetic) oil is recommended for most break-ins. After this it is recommended not to perform your break in on the high way. Remember to keep peak RPM low with occasional and brief entrances into the high RPM band, and allow RPM to chage frequently when under load (City Driving). I do this for about 500 Miles, some will give other mileage, but I think it depends on the engine and what components are installed.