Anything can be fixed for the right amount of time and money (and spare parts or donor cars).
But I'm pretty sure that one's toast by almost all standards. The crease in the roof gives away damage to the understructure of the roof, which would tweak the whole frame, probably in several axis (its pushed in, but as it crumples and shortens it would likely lift the corners of the frame toward it). Also, in the last picture you can see that the floorpan is buckled, a sure sign that the frame is damaged pretty significantly. And its just a '73 or '74, which means its not something worth investing the money on fixing. If it were an original hemi car or something it might be worth the undertaking, since its not the price tag to fix it would exceed the value of the car many times over. It would take years in the shop to get that one anywhere close to square again.
Also, it may not have been a single pipe. Only one shows, but that just may mean the tailpipe/muffler fell off on the damaged side...
