You obv do want to get into a pissing match cause people keep giving you examples and you keep saying that it cant be done. If you do things right the first time it is EASY, if you build a motor once, dont make the numbers, then buy parts again to make more power then yes, thats the HARD way.
331ci, good set of 205cc heads, victor5.0 or TFS R intake and a custom cam and its done.
My motor made(a little bigger than a 331) 440hp with TFS cnc'd 205's a 282XR cam and a dual plane with a spare untuned to my motor carburator. It made 440 HP at 5900 rpms, i wasnt concerned about the power, i put it on an engine dyno to break it in and make sure nothing was leaking, i was giving up alot of power with the dual plane, and my motor is only 14 CI smaller then a 331.
Here is your "450"hp 331 with a solid cam that is revving to 7000+rpms. In reality its a 331 that peaks at 7300rpms and makes 540hp with NO EXOTIC PARTS, which to me makes it pretty easy, you can believe it or not, but its been done.
http://www.stangnet.com/mustang-forums/803357-awesome-article-engine-masters-built-331-a.html