best flow intake

Raw out of the box CFM (I'm sure I'll get some argument here), I believe are the Holley and Trickflow intakes. That said, I would try and figure out what combo you eventually plan to run and try to find an intake that fits that combo.
 
Have you considered either the Trickflow or Holley packages? Heads, Cam, upper and lower, timing chain... whole nine yards all designed to work together. Normally aspirated, I can't see how you could beat it.
 
I dunno how much truth there is to that. My aluminum heads make me hell of allot more power that my stock iron heads ever did. As far as durability goes, I imagine that I'd have a much tougher time damaging my cast heads with saaaaaay a bullet from a gun than I would my aluminums. A,uminum heads are all the rage... they're light, easy to machine, and mate well on blocks that are less than perfect in a lot of cases. The only recommendation of cast over aluminum that I personally have read, was from a supercharger manufacturer that said that cast heads absorb and disipate hear better than aluminum. I think that that's debatable as well. Absorb... maybe... I find it hard to believe that cast iron would disipate heat more readily than aluminum though.