Thanks the articles and Jay's information confirm what I read.
I checked the Shell web site. The Rotella T single grade straight 30wt is listed CF-4, CF-2, CF and SJ. This may be old infomation and it doesn't mention the concentration of ZDDP.
Unfortunately, parts suppliers only carry the latest oils, usually API SM. The local suppliers stopped stocking racing oil. Castrol USA doesn't list any vintage oils. Looks like mail order racing oil or ZDDP additive.
Peter