You got some good advice here. The Big bore kit will go along was to giving you the extra ummmph you are looking for, basic fact is , there is no replacement for displacement.
I am also a big fan of raising compression ratio's as well, my preference is to do it with pistons as opposed to having the heads "shaved", and depending on how in depth you want to get (and your budget) you can raise the compression height of the pistons.
Some polishing work in the intake and exhaust bowls of the heads will go a long way to increasing the flow with out dumping huge amounts of time and money into a full manifold match, port and polish job.
But I guess the best advice one could give you is to keep your build balanced, simply bolting on a set of Zippers full blown race heads for instance, with out doing anything else will give you better performance but is that really the best way to spend that much money for the return you will get? The most important part of your build will happen way before you ever pick up a wrench, it will be the planning that goes into it before you spend the first dime....... JMO
