My Grandfather has three Kadetts that he wants to sell. The are similar in years, he says between 1968 and 1971. Two have engines and one doesn't. One onf them was running 5 years ago when he stopped driving it. All three have some body damage but have lots of salvagable parts. They are located in North Dakota. I don't the first thing about Opels and don't have the slightest idea what they are worth. Please help!