Re: Max HP from Std heads
If you are starting from scratch (ie have no bits already) and are doing it on a budget I vote for the 2V CC (302) heads.
Go for a small mechanical solid, flat tops, standard bottom end, decent single plane manifold, extractors, 650-750DP Holley and get a mild port job done. With the right cam you should get an honest 350-380HP out of it with lots of torque as well...
Generally speaking a bigger budget means more revs, more HP and the need for 4V heads..