I found a guy with an original ram air hood locally. The metal underside has been cracked some how and needs to be repaired. Would $700-$800 be a fair price for it?

 

If you're talking about the hood I think you are, that's not the only issue with that hood. Also, has a grapefruit size hole through the fiberglass and the fiberglass top seems to have separated and would need to be reattached to the metal frame. I looked that car over a while back and had thoughts of extending an offer but decided to pass. If you can't do the work yourself, you're going to pay a lot to get it fixed. Still, an original hood as you say but in extremely rough shape IMO. Good luck whatever you decide.