well an old Ford 427 made anywhere from 350-450 hp in Pushrod form not the over the counter optioned SOHC versions, the new V-10 427 makes 590hp, the Chevy LS7 427 7liter V8 makes anywhere from 500-600 in factory trim.
Oh and the new Ford GT only uses a 351ci block
EDIT: here are a few different 427 blocks for you to look at...
All can be found here aswell:
http://motorworld.net/forum/showthread.php?t=27389