A stock RR cam will really not have much of a lope, and should still have some decent low end? Any chance you've put a vacuum gauge on it? It may help us to tell if it's some type of aftermarket grind?
Either you have a "bigger" racy cam grind installed or you need to tune that baby a little more. Meaning I'd try bumping the initial timing as far as it will go without pinging.....Might end up in the 16/20* range, who knows, but if the engine is happy there, just make sure you modify the total timing to be not more then 36/38*. And of course, any chance of vacuum advance being involved should be blocked off for your testing at this point.