[keg65]

check for rust, always a problem with the old ones.
1000 seems a bit too cheap, especially if it is running.
I would really look for structural damage, previous wrecks or really bad rust. If it looks good, doesn't mean the problem isn't hiding under body filler.
For 1000 it may be a good start for a project car, so if you are willing and able to do the work, its not too big of a deal to fix everything. Most parts are available aftermarket, you can even get an entire 67 fastback shell in reproduction, it cost about 14K, but anyway.
A starting price around $5000 would be more like a good driveable car.

As with any old car, first things first. Even though it doesn't show much improvement and you don't go faster, BRAKES are the most important, as well as steering and suspension. Start there, upgrade if possible.

Going fast is only good if you can stop and steer, I already made that mistake with my first Mustang. Also if it does have rust, don't just cover it up. Replace the panels, stop the rust, protect the metal.

Good luck