I bought a 75 Dodge Dart new, engine was fine although I did have to replace the starter before I sold it.
The car had problems, it came from factory with 2 left torsion bars (which the selling dealer was unable to figure out) and the front drum brakes totally stopped working if they got wet. When there was very much water on the streets, the car basically became undriveable because of the brakes.
A few years ago I bought a low mileage Volare wagon with the slant 6. It was totally awful. In 4 months it quite running and left me stranded 5 or 6 times. I was really disappointed in that one.