I just bought my 72 Challenger in April for $5500.00
It's an original 318 car. But now has a 340 that was rebuilt about 50,000 miles ago. It's got headers and a high energy cam, the previous owner didn't know the specs. The 904 automatic trans was just rebuilt and has a nice shift kit in it.
It has some big Front a rear after market sway bars that make this thing handle killer!
The interior needs new seat covers, and I just got new carpet kit on Fathers day from my kids
The only major thing I've had to do to it since I bought it was rebuild the front suspension.
It needs some rust repair and then a new paint job.
It runs great and I have a blast driving it to work every day.