And Dodge 2.7's only failed due to the PCV valve, and a different oil could offer no benefits. The 5.7l in the 300 must be changed at 3k, no oil could live past 3k miles. GM L76 DOD problems could never be helped by anything. Engines never wear Nobody should ever exceed (or shorten) the factory service interval. Engineers never have any other pressures on them, they only ever design a perfect specification. BTW, backspacing oil is done because why? Did the engineer make a mistake? Did average aoil qualities change? If the owners manual is perfect, why would they ever change it? We should all drive our car in the average manner, in the average climate, the average amount of runtime, with the average number of passengers, and carrying the average load. AApparently the troll needed attention.