tryna get close to 400 hp...Wanna work out my 973 casting 318 heads

Build for a powerband not some vague hp goal basically it seem you want a srong running but streetable 318. Build for idle-5500 if you do it right 350hp shouldn't be a problem, 9:1 high lift 268 cam, headers, etc... KB pistons zero deck and 360 heads will get you 9:1.