Sears Spectrum 10w40. As someone mentioned, it came in 24 qt. cases and they usually had a big sale on it once a year. In the 70's, I often did my oil changes at my parents' house. So, I "borrowed" some of dad's multi case stock of it now and then. Cardboard quarts with metal ends. Used a puncture spout.
I'm not clear on it any longer, but I think there was some real or imagined problem with some of the Spectrum oil at one time. I sadly remember the bad batch of QS 10w40 in late 1980 or early 1981.