Oil,doesn't matter for left or right on 50 or older. 51 and 52 have four cylinders in rear, and they are diff between them, and 53-59 have same type, but diff #'s. I got my #'s from OlBlue on this page. The #'s given above are right. Anything in yards is gonna be too pitted to use, you'll need new or sleeved for those.
