[85vette]

On the other side of the coin GM along with Porsche, Bentley, Toyota, Lexus, Daihatsu, Hino, Chevrolet, Cadillac, Opel, Vauxhall, Buick, Holden and Perodua(make I've never heard of) have designated Mobil 1 their "Official" oil brand. From an engineering standpoint along with the bean counter standpoint I would want to choose an oil that would not invite failure to my engine, in part to reduce warranty repairs due to lubrication failure and also because a product that does last beyond the warranty period is just plain good advertising. We all know that bad news travels faster than good news. Honestly, ALL oils are so much more advanced today than in the early days of the internal combustion engine that I doubt lubrication failure is much of a problem now.