The port work is done to your cylinders, not the head. Recommend you to take it to a reputable builder. Look up porting and who does it, on this page. Yeah some port work can run you around $400 including all your gaskets, bore and hone. You might consider doing a top end for another $150 for the pistons. These prices are if you do the installation yourself. Pretty simple, Clymer's definitely would make it cake. And some larger jets would be needed, few bucks.
:beer: