Check out the frame rails and the fenders lips inside the engine compartment. Look for buckled metal often covered by spots of rust. These are tell tale signs that it has been in an accident. If you see them, ask the owner if it has ever been in an accident. They should be upfront with you about it. Just about every late model fox stang out there is going to have been in a fender bender sometime. Mine was in two before I bought it. Don't freak out about it, but check the repair work.
Were Ford parts used in repair (they're usually stamped with the ford logo)?
Do the seams match on either side, and are they uniform?
Do the doors sag?
Also, when you drive it (you have to drive it), drive it with the radio off and with no one taling. Listen and feel for vibrations. Sometimes they can be ruled out as tires needing balance or warped discs under braking, but others my tell a more serious tale.
Is the engine covered in oil?\
Look under the car at the frame rails. Are they straight? (there will likely be dents in them from using a car jack on them...this is normal and o.k.) Is there oil covering the back of the motor and front of the transmission? This likely signals rear-main seal.
Remember, most Mustangs leak something or other. A drop here or there often won't hurt and is normal for high milage motors, but pools of fluid on the ground must be checked out.
I guess last of all, if you have any doubts, take it to a mechanic that you know and have them look it over for $40.
--nathan
------------------
--silver_pilate
'91 GT, Built 306, Wolverine 1087 cam, ported Windsor Jr. Irons, and all the goodies...click the link to the left to see a full list of my mods...
Tried and True 302 Being Built to Outrun You! heh heh heh...
--Texas Panhandle--
Check out my site