I can tell you a few things for sure about motor oil.
First, when I was much younger, the hottest cars around these parts were '69 Chevelle's. A neighbor who was older had a yellow '69 that was beautiful, and his friend who owned a service station had one of those chevy blue/green '69's with the 350/325HP engines. The fellow took off out of town from the service station with a swish, while the owner was changing the oil in his Chevelle. Well, we kids went in and started to torture him about how that yellow Chevy could outrun his, and after just a minute or two he was in his car and chasing the yellow car down the road. Imagine our surprise when we went out into the lube bay, only to find 6 unopened quarts of Gulf Multi-G setting on the floor by where he'd been working, and the oil pan plug laying on one of the lift tracks! When he left town, he wasn't exactly taking it easy, as you can imagine, but he made it a good 12-15 miles before the thing suddenly started having what can only be described as "major problems". One motor ruined, one very disgusted owner, and kids who stayed away from the station for a while to avoid certain retribution for teasing, (even though we had no idea at the time what was happening before hand).
Fast forward thirty years or more, to about 2002, when I had a 1998 Ford Ranger 4X4 truck, which I dearly loved. Religiously taken care of and 98K miles on the clock, this truck looked and ran like new and never used oil. Me and my working pal, are leaving work one day when we hear a funny "snap" noise when we're just pulling out of the parking lot. Not seeing anything obviously wrong, the truck runs fine, for get this, ONE mile, probably less, and everything starts to go to the crapper, shudders, knocks, another "major problems" day, it had just sheared the oil pump drive rod, and we stop. After I get the top of the motor torn down and not finding any real damage, I can't get it to stop knocking real bad, apparently spun a rod bearing, so it gets traded off in defference to pulling the motor and putting that kind of money in a truck with almost 100K miles.
Was oil better in the late '60's that it was in 2002. I honestly don't remember what I was using then, but it was name brand dino. I only ran it a few minutes under what would be considered EASY driving, in the '60's he was running HARD trying to catch his nemesis, go figure.
You just can't figure what's going on in an engine, but I'm glad I never started up my Ranger after draining the oil to "get all the oil out", or I'd have been sorry quick.