The above mention on the aluminum heads. You'll spend a bit more on the check out. Prices vary by area. Add it all up and the iron heads ported are cheaper with better flow but there probably at there max at that point.
No kidding I'm was in the same boat with mine but I have aluminum heads cause the engine builder that I have said that spending the money now for aluminum heads and intake will save a lot of hassle and headaches further down the road