Fully port them?? And yes its worth it, a member on this site broke records with hand ported in his garage stock 96 gt NPI heads. So yes port and polish them, get them cleaned up hot tanked, decked, rebuild them all new springs guides etc... mean cams.
Port 'em, but "polish" isn't worth the time. Anyone who's worth paying knows what to do, like MHS. Call them, tell them your budget, and see what they say.
I'm guessing if you are porting you might as well go with new cams & springs. Because I'm thinking the gains from cams is more than just a port job on stock cams but the money for porting alone is greater than just swapping cams & springs. I'm not saying that's true, it's just few people report numbers from ported heads with stock cams but many people have swapped cams without porting and see real gains. My understanding is that you need to strip the valvetrain off to machine the ports, so you might as well do the cams and springs with the port job. If you are on a budget, just swap cams and springs.