Slightly strange head flow question.

ok im going to give this a shot. i feal the anweser to your question is short and simple. lets say you have a pair of w2's that you hust sent out to a reputable shop and had the ported and flowed. Lets say the shop proves the heads to peak flow 300cfm at .600 lift. now considering the WHOLE rest of the car is set up and dialed in and taking into acount valvetrain geometry and lash, youd want the cam to open the valves slightly more than that .600 lift peak flow. so lets say you can get .625int at the valve there you go. your reaching the full power potential of the heads. just my 2 cents