Tiny, I thought I'd find all kinds of threads on this subject, but nothing pops out. However, you remember Niagara, don't you? He had that bright yellow '50 and was a frequent poster until he sold the truck a ways back and got a '61 Buick. Anyway, we're still in touch on a regular basis, so I asked him what oil he put in his truck. He sent me this link. I think it explains it very well.
Bob Adler's Oil Article Hotrod, why would anyone flame you for providing input on a subject like this? I thank you for your contribution.