cast iron heads vs aluminum for stroked 340

As to the aluminum vs iron, Its my understanding that al sucks heat out of the chamber, to the tune of being worth about 1/2 to 1 point of static compression.
On a stroker where compression builds rather fast, depending on your combo, you may be able to get away with that much more Scr before getting into detonation, using aluminum heads.
Thus the engine may be easier and/or cheaper to build with the al heads. It really depends on your compression requirement to achieve your target.
For a DD or pkg thats going to see some mileage, you might be able to reduce your octane requirement, with al, to reduce your running costs.
Its not really complicated, but does require some forethought. But somehow I doubt this applies to your goals.
It did to me and my little 360. With gearing and a sharp tune, I was able to get 32mpgUS, and still go 106 in the qtr.
Of course at 550/550, you're probably thinking "what has this got to do with me?" Well, nothing, today. But what about when we go back to the long gas lines of the previous Gulf wars? It seems to be coming...........