[Super73]

Ok, it is my belief, (general rule here) the better the heads flow, the less duration you need in a cam to achieve the same amount of power of a less head/bigger cam combo (assuming port volume is the same). How ever, valve event's will still dictate where the power is made. Flow ratio also comes in to play. Lifting a valve to Marv's point, allows you to use more of the heads flow at given lifts.. IE the faster it lifts, the more time it's spent at .300+ filling the cyl more efficiently, the higher it lifts, the more time spent at max flow on the head. There is more to it than that, but with out writing a book (or reading one that's already written) it's not worth totally getting in to.

With that being said, choosing a cam with out knowing what heads you will be running and what your goals are, will prove to be dificult to do.