unless you are buying it for a donor car, the rust is the most serious issue that you can face. I've owned a 71 1800E and a 73 1800ES. The es looked okay, but if I had bothered to try jacking it up before I paid for it, I would have discovered that the rockers and spars and crossmembers were rotten through and structurally unsound. The 71 also had some bad rust, but it was a parts car so I ended up stripping it entirely.

So, be sure you jack that car up before you buy it.

The "manifold air pressure sensor" is also the critical heart of the injection system and is no longer available, so if it is bad, you'll have a hard time...