If he was going to scrap them why do you want them? Are you SURE they are properly done and not some yahoo with a die grinder or something? At any rate something seems very fishy for fully PP'd heads for $500. If you do wind up getting them I'd take them to a professional head guy and see what he thinks. Back in the day I learned the hard way from a professional porter to not ever buy ported heads from a dude who did them on the side... And this guy was supposed to be legit too. Never will make that mistake again.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.