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

I think my 318 was about 330-340 horse, I used the 302 heads with stock valves and did some porting. I used domed pistons and had 11.5 compression with a comp xe-274s solid cam with .500 lift. I think you will need at least .500 lift to get to your hp goals, and it will take more rpm than a 360 to get 400 hp.