Comp Cams Xtreme Energy

I've run 3 XE cams in my engines, a 360, 440, and 451, a buddy of mine bought a dart with a 360, it had a XE274H, stock rockers, none of them made noise, 270lb spring pressure will be fine with that cam, my springs were 305lbs open with an XE284H and it was fine at 6300 rpm.