318 boost

i have a 75 318 2bbl. was thinking about the 302 casting head. is it worth it? is there anything that has to be modified? i have a holley 600 and due to budget it has a 3" single exhaust with flowmaster y pipe with manifolds with a 50 series 3" flowmaster muffler. i was really only going to get wrecking yard 4 bbl intake, remove the holes and port match the heads depending on the intake i get. also going with a small comp extreme cam they recomended for this car. any help would be grat as to if its worth the other heads or just stick with whats there. thank you.