Had a 52 dodge truck,in High School, we just used plain 30 wgt, and many more cars and one f100 ford truck. Now I'm 63, might have used STP once or twice, nothing to speak of. In fact oil and it wgts were never a big topic growing up, till about 1967 and for some reason I got interested a little. MY friends in the Navy in Florida used Havoline mostly. I got into expediting a few years ago and now oil types is a big deal. Well better late then never, but doing the family thing for years, oil was not that important, just so the engines ran, was ok for me, but thats all changed now.