[red82gt]

FYI, my flow #'s are enough to support 500 hp with the right cam, induction, etc.
My car leaves a stock 5.0L way back in the dust so I'd say they're not short on power. It is more expensive to have iron heads ported than aluminum but iron does retain heat better so you can make more power with iron heads (all else being equal). If you can afford the AFR's I'd probably go that way but if you want to save some money, a properly set up combo with ported GT-40's will work.