older aluminum heads vs newer ones?

[cooguyfish]

I have read the the 2000+ heads are much better than the older aluminum heads and I was curious what the actual differences would be? Are there any advantages to any style of heads? Is one better for fuel economy, and one better for power? Is one better for top-end, and one better for low? One better for boost, and one for N/A?

Thanks

Edited to ask, I am asking because I've collected several sets of parts and I'm building a few different engines for a few different cars. I may also build more than one engine to see what kind of power different combo's make.

[robertisaar]

the 2000-up heads and intakes have larger ports, so they can make more power up top. fuel economy wouldn't be much different, if at all, between the two. the newer heads might have a compression advantage though, i'm not entirely sure on that one though...