In high school, one of my friends had a Dodge Dart with the slant 6 in it. He wasn't a real savvy sort of car owner, so I think that engine was just right for him: one day he was driving out of the city into the countryside with his girlfriend when the Dodge stopped running suddenly from 55 MPH, so they coasted to a stop on the side of the road. After 'parking' awhile they decided to go for a walk and then returned, and the car started: he drove it back home again (about 30 miles). The next day I happened by his house as he was changing his oil: when he pulled the plug only a small dribble happened for a few seconds, about 1/2 quart was it. (It did burn, and leak, oil quite a bit). He drove it another 3 years after that.
About a year later I was working at the bike shop in Pekin, IL when a guy brought in his CL77, complaining that it would only run about 30 minutes at a time and quit, plus he wanted an oil change. After it cooled off I pulled up a drain pan and pulled the plug and...drip, drip. That was it: there was maybe 1 ounce of oil inside. I put in the normal 2 quarts and cleaned the spinner filter, set the points and checked the valves (they were fine), and he rode off happy. I told him to check the oil once in a while. About 4 months later he came in for another oil change: that time it had full oil still inside, but he said he had added "some oil" since the last time he was in. Tough engine!