Used P headers?

how much should I expect to get for a set of Mac shorties for gt40p heads? A few thousand miles on, and a very light coating of rust. And, can headers made for p heads work on normal heads with no spark plug probs?
thanks
 
Sorry, I can't read sometimes. I figure do a search on completed auctions on eBay. I figure $50 on up. Getting your headers to work on P heads? You would have to check with Mac themselves. I know the back tube on the drivers side would tell you if it will work. You can tell if it will not work on your "p" heads. You can't put a plug wire on it.