318 v 360

you'll need 225cfm on the intake side of the heads, 284*+ duration, .525-.540 lift, headers, 10.2 comp minimum, 650-700cfm carb.

I don't normally say this but go with 360 heads 1.88/1.60 valves and minor bowl work, don't touch the rest of the port if you can help it.
the other direction with mag heads would be a down grade in the sense of valve train parts and flexibility, but they do have a closer matched port volume, however if you have compression like 10.2 or better w/ 360 heads and a good tune, right manifold, timing and such..you'll be good with no sacrifice to low end in comparison to the mid range & upper rpm power.jmo

the more I think about it, the more ideas I have about this 318 450hp thing.