Except my intent ain't to discourage the OP, If he likes the idea of a 400 hp @ 7000 rpm with 5.30 gears and wants to build it, I'm all for it, If not I'll try to help with option B.
I tend to agree with some of AJ's basic premises just not how he applies it.
I have followed a few hot rod 273 build threads here on the site and I have yet seen one get finished, ran on a dyno, or at the drag strip to measure horsepower. To the OP, build what you want , how you want but remember, it's only a 273.