We all know how touted M1 is all over the oil bottles, commercials, used by over half of NASCAR teams, official motor oil of NASCAR etc.. But how true is this? And what grade would they use in those high performance, high revving V8's? Or is it just a huge ad campaign to sell more oil by XOM? Since the majority of consumers, mechanics included, don't know much at all about oil, or care about ingredients/performance properties in the engine itself. "If NASCAR uses it, it must be the best!" Type of approach. I've kinda distanced myself from the sport since Earnhardt Sr. died, but I do recall sometime in the 80's or early 90's, in an interview, Rusty Wallace claimed his team used M1 15W-50 for the first time in their car and it made a huge difference in engine performance and allegedly helped them win more races. Supposedly kicking off the synthetic oil craze in racing at that time. I wasn't very enveloped in oil during this period, and bought whatever was cheapest/sale so all of this flew over my head. Also obviously before the internet and having all this research at the click of a mouse like today. These days, I'm a pretty devout M1 user myself in my Tacoma and motorcycles, but not a rabid fanboy either and open to speculation and discussion about what's what. This is BITOG after all! As you can see in my sig, my Mustang uses regular old Pennzoil rather than Mobil Super.