I was asking for actual already built 600 HP 400's
I'm sure the compression would end up around 11 to 1, but the fact is people aren't building stock stroke 400s for high horsepower because it is much easier to go with bigger cubes and have an engine that doesn't have to like on the ragged edge to make 600 HP and that kb 240 hypereutectic piston with those huge rings would be on ragged edge. That's my entire point since my 1st post on here about. It isn't easy, it doesn't happen with off the shelf stuff and for usable HP on the street as the op wants it isn't there till he's already beat.
But yeah in theory Indy 440-1 would be a great head, a tunnel ram and a solid roller cam, a great oiling system it would probably make more than 600, but again it's easier with more cubes.