400 h.p is not that hard to achieve. LA eng stroker crank 4 in and +.090 bore job is 400 c.i. Cyl hds flow close to stock edelbrock LA's after a good port job and larger valves.Brand new intake available,modern dual plane.Cams,headers, roller rockers are available.One I was involved with actually made 505 h.p with a roller cam.