My '59 Galaxie's shop manual recommends 20W oil for the 292. I have googled and forum searched but have yet to find any clarification as to whether oil weight classification has changed since then.
What I mean to ask is, does the oil referenced by the manual have some other modern equivalent?
Like, 20W in 1959 = 40W in 2009? I find it hard to believe that what we today refer to as 20W oil was recommended back then, seeing as most modern engines with their tighter tolerances and such use a 5w-30, and only a few of the newest cars I've encountered take 5w-20. Thanks for patience with yet another oil-related thread! I know there are a ton of them floating around on the 'net.
1954 Crestline Victoria 312 4-bbl, 3-speed overdrive