I want to use one of the 3 brands of conventional oils out there, and stay with it , how ever I do not know the specs or stats on these oils , can anyone tell me which may be the best of choice to stick with to get at least 200 K miles from my engines with a faithfully oil and filter change at 3000 miles. the examples of oil are Mobile 5000 conventional. Castrol conventional, or Valvoline conventional and I use only 10 X 30 weight that's recommended for my car and truck.