Well, it's primarily a street car with possible occasional strip use. "We" spent the money for aluminum in order to increase performance (via porting). Iron heads are not only limiting but ridiculously expensive to port to relatively modest aluminum head levels. The weight loss is a bonus. Similarly, the glass hood has a scoop built-in to allow more carb/manifold clearance and admit more cool air, without having to spend money and time hacking up the original flat steel hood or paying a body man to do it. Again, the weight loss is a bonus.

You pointed out in your earlier discourse that structures work as a system. Same with every decision to buy, modify or replace parts - none of that happens in isolation.