whats a good set of heads

Well...for cfm gain...the 360 heads milled down equal chamber volume as a 318 head would get you ahead of a stock 318 casting by 35 cfm, 210/215cfm 360 HEAD w/1.88 as opposed to a 318 heads 170/175cfm w/1.78 fwiw

Its safe to say that the cheapest heads with least amount of modification good for 400hp are run of the mill 360 heads.