Looking at the Castrol site, they don't say, but I think it is not a suitable oil for anything older. The Rover V8 is really a 60s Buick engine, probably designed in the late 50s and modified over the years.
So that is probably a no!
Mobil 1 Racing used to have decent ZDDP levels when I last looked into it. As a rule, ZDDP poisons catalytic converters hence the low levels in most modern oils.
