Randy,
it looks like you are loseing the forest because of the trees.
flowing/porting your heads will tell you what you can have/make.then spend the coin on a cam and decent carb.
heck i just recammed a 440/512 and picked up near as 40hp with a still streetable solid.Dwayne Porter did dress up the heads a few years ago.
you may even want to look to your fuel system and suspension to pick up more et.
good luck

Tex