You could also look at NADA. You would have to go into the "Classic Car" tab in order to find pricing on a 92. I know you asked about BOOK values, but the pricing on these Foxbodied Mustangs are all over the place depending on condition, mods, etc. IMO, in most cases, I would not base my purchase on a price given to me by NADA or some other price guide. Just check around on eBay, Autotrader and your regional Craigslist ads (expand the area as necessary) and you will get a better idea of what that car is worth in your marketplace.