The SVO Mustang didn't come into production until the 1984 model year. Two SVO's were made for racing in 1982, and 4508 streetable versions were made in 84.
If you mean a turbo or 79 cobra hood, they can be found easily. The 1979 pace car and 80-81 cobra hoods are getting pricey but they are still around.
If you find a nice one, you had better buy it. They aren't going to get any cheaper.
there are people that part out SVO's on Ebay and I have seen hoods there very reasonable, but the shipping would be expensive. your best bet is to get in good with a local pickapart and have them call you the minute they get in a 84,85 or 86 SVO. There is no real source for the hoods, you just have to get out the word and one will pop up.
they do make a SVO style fiberglass hood for regular Mustangs, you can find ads for them in Mustang Magazines.
Check the group below, the members might have one.