AutoMechanic
Site Donor 2024
Probably whatever was available. Some of the old timers have told me back in the 1900s-70s in shops they just had bulk barrel oil that went in everything it was just what they had at the shop. No specific ratings or whatever it was just what is in the barrel. Or you could buy cans of whatever at the store. I’d probably use Castrol or Valvoline possibly Pennzoil if it was the 1950s and I was doing it on my own.