Funny thing is they kept talking about the iron heads flowing a few cfm better, BUT if you paused the tape when the flow table was posted that was only true at the low to moderate valve lift. Between .5 and .6" the situation reversed and the al heads flowed higher. Not that the differences should have mattered enough either to impact the conclusions.
There still are some reasons to use iron heads in certain situations (like class rules) but that's not relevant to this thread.