Well I just recieved a email back from RyanJ and I was told building a 500 horse 360 based 408 for 5K is fairly simple and reliable as he built one for his daily driver. The cam only had .525" lift as well.
Well,if making 500 peak horsepower is your goal,it's easily done with a 408. But you have to remember that what makes power is the heads,and OVERALL h.p and tq under the curve are far more important than peak #s.
I think a VERY torqeuy 408 with an extremely fat powerband could be built for bargain basement beans by using EQ heads.