1972 318 need more power

have a stock 318, (72) it has a elde intake and 4bbl carb now, and it sounds like someone put in a mild, not wild, cam. I wouldn't call it a much of one. the rest appears stock. have not checked the heads but guessing stock till i look at the numbers. I've has some tell me to find a v6 out of a dakota or something and use those heads and get more kick out of it. 1. will they fit?, will all the accessories on the 72 bolt up, like AC etc. 2. would they be worth it? I was thinking that perhaps some aftermarket heads might up the compression some and not break the budget. want to keep it "looking" stock as much as possible. got any ideas. (not wanting to get rid of the current motor(orginal to the car). do not want to rebuild the same.
Just looking for a little more bang for the buck and not break the bank. tks Mike