Looking at today's top of the line chevy heads and even ford stuff you can see it doesn't look much like the heads used in the 60-70s. I see 900+ hp BB chevies using spreadports and combustion chambers that look nothing like a set of stock chevy heads. I have a 900+ hp pumpgas hemi that uses a set of street replacement heads that aren't much different than the first set of 426 hemi heads used in 1964. I assume the top of the line head for a hemi NA is the millenium head, which is a step in the right direction toward fixing hemi shortcomings. But, why is there nobody looking to give the hemi head some updates, like maybe modern oval pro stock style ports or smaller chambers and moving around the valves? I would guess there just isn't much of a market or somebody would or is it not possible due to design limitations? Even the boss 429 has been redone by Kaase with a modern chamber.