Hoyt,
I understand your point about 50W.
"When you see a W on a viscosity rating it means that this oil viscosity has been tested at a Colder temperature. The numbers without the W are all tested at 210° F or 100° C which is considered an approximation of engine operating temperature. In other words, a SAE 30 motor oil is the same viscosity as a 10w-30 or 5W-30 at 210° (100° C)."
Sorry about adding confusion to this discussion.
It was straight SAE 50 oil that I used to use in the late 60s and early 70s.
And, I think I also used a "multi-grade" SAE 50 oil (before the "W" grading was around) for the same reason (higher oil pressure in an old engine). This oil was recommended to me by my brother-in-laws dirt track "pit crew" around 1970 for use in my worn-out 1948 216.
