"Not to go off-topic, but “Pennzoil myth”??? High paraffin base stock that leads to sludge/varnish under high heat???"
Kinda sounds like you're into it.
Note how many race oil companies come out of Pennsylvania. Pennsylvania crude has some of the best lubrication qualities of all crude on the planet. If it was actually bad, they would have fixed it decades ago.
Not going any further with this.
just like the "quaker state" myth..............
both of these myths were ultimately chased back to bad maintenance, [not changing the oil] and short trip driving, not allowing the oil to get up to proper operating temperature.
these myths were rampant in my junkyard ownership days [1972-1984/5], and we sold a lot of engines because of them. knowing several people well that bought engines from us, it quickly became apparent no matter what oil was used, not changing it and short trips did engines in.
remember now, back in those days, the machining process was totally different than today's, and if an engine lasted 100k, it was because of good maintenance and/or long drives getting everything up to proper operating temperature.
and as above, that's all the further i'm going with this.
