As much as I like Mustangs; that looks like quite a bit of structural damage; more than I'd want to deal with... floor pans and even quarters are "structural" members on unibody cars. Pans are available ($mile as you grab your wallet), quarters -last I heard- aren't. There's a '72 H-code coupe that's been for sale in a front yard two blocks from me - for two years, not a serious bite. Those who are interested in the price stop when they see the folded-up right quarter and think about finding a junkyard replacement.
IMO, I wouldnt give more than $200 for it. That thing is a headache, moneypit, and a future half finished project. All in one.
The aftermarket is not as good for the later classics, You will end up buying a complete donor car that is in better shape. The fact that there is no title would scare me away as well.
Here is my $1700 find. its a 351c car. with some rust issues in the floor pans.