Many stout performing 440's were built with factory heads before aluminum heads came into the picture. As said above, depends on your goals and what it costs to rebuild your heads. Also, will the stock heads have hardened valve seats for unleaded gas? Right now in the classifieds, there's a nice set of fresh 906 heads, ported with bigger valves for $750, cheaper than any aftermarket options. Of course, you can easily take ~200 pounds off the front of the car with aluminum heads and intake. I doubt you'd notice a difference in performance with a <
[email protected] duration cam between iron and aluminum heads.