I've searched around and have really not found any postings with specifics as to why Chevron conventional oil is such a good oil. I'm not saying its not--not at all. Its just that I've never heard much about the oil before coming here. My father-in-law is a mechanic and has always sworn by Valvoline (and also likes Castrol). When I told him about people really liking Chevron oil he was curious why. Can someone fill me in? Thanks!