AFR Heads

Read the paragraph below 6.0 Valve Sizes.

Then think it through. If we installed a 2.125 valve in a 273 head, how good would that be?

Valve size is as much related to port size as it is bore size.
What does that got to do with if cfm has much merit when it comes to performance, I started off saying I basically agree with but cfm has more merit then you seem to give it credit for.

CFM, velocity, port size are interrelated, if you know two of them you basically can figure out the third, you can't change one without at least effecting another. CFM obviously matters and for those that are not racing especially in a highly competitive race classes that has especially vague performance goals could do worse than shop by what a head flows.