Let's expand on this a bit.
How about a moderate budget build starting with a Gensis iron 427 block. Could a very streetable engine be built using a 428 crank, I rods (aftermarket or Ford), Edelbrock heads and intake, Canton pan, hydralic cam with flat tappets, and Ford type rockers?
I have been thinking about this for a few months and think you could easily get 450hp for less than $9k in parts. I assume an engine builder would charge another $2k for assembly if you can't do it yourself.
Check this link out to a Carcraft article. They built a 500hp 390 for $6000.
http://www.carcraft.com/techarticles..._fe/index.html
Please feel free to shoot this full of holes.
John