I stumbled on a deal on some old motor oil at a flea market over the weekend. Valvoline 10w40 in a can. 20 quarts for $2 a quart. I am thinking that if it was in a can rather than a a plastic bottle it should still have zinc in it and be good for my Y block. Can anyone confirm that? I can always use it in my '56 John Deer 50 if all else fails.