you can save some weight by going to aluminum heads, and the heads you have listed are decent heads, your route isn't the most cost effective way to 400hp though, I was just trying to help your bottom line.
As far as pump gas and Vortecs, flat tops and Vortecs are ran a LOT. anything larger than a 268XE cam seems to run just fine on premium. If you are going for high RPM power you could probably get by on 89 maybe even 87 depending on a lot of other factors.
It all depends on what route YOU want to take. I was just trying to show you a cheaper route to make the 400hp you are after.