I've been looking at camshaft profiles lately as well and I agree there seems to be a big jump in duration (at .050) between a "powerband" ending @ 5500 rpm or less and a "powerband" ending @ 6000 rpm or more. This seems to be "generally" true for most cam companies. example:
Crane's H-272-2 = powerband 1800-5500rpm = dur at .050 (216/228), 112 LSA
vs
Crane's H-234/3250-2-6 = powerband 3000-6000 = dur at .050 (234/244), 106 LSA
seems to me there's some room between those two profiles for a nice design.
