I've always been told that the current API rating was retro active, and that it would meet or exeed the requirements of the older oil rating. Personally, I'm suspect of poor camshaft quality, rather than any oil problems. Seems convenient that the cam companies blame failures on an "oil additive" problem than admitting to a manufacturing issue. I'm running Valvoline 30wt Super HPO, made after 2005, with no issues at all with the cam. I'm running a Howard M4F 3/4 race cam from Patrick's. It's a solid lifter flat tappet cam, set at proper clearances. The only problem I've had was one pushrod that the end came apart on, other than that-no problems.
I think the real trick is to do proper break in, and follow up with regular oil changes as specified by the vehicle manufacturer.
