I dunno, Gary. the reference dates from 1969. How much more antiquated to you want? I mean, like, Castrol GTX was a 10w-50 then, and probably sheared to,like, wow, a MMO-like viscosity in a 1000 miles or so. No wonder I was rebuilding the R-8 Gordini every 10,000 or so.
You may want to check...