The slant 6's seemed bulletproof.
My first car was a 1960 Valiant with the "big" slant 6. I paid $450 for it in 1966 with 50,000 miles. I drove it through college and sold it to my brother. When I got out of the Navy it had 255,000 miles on it with no major repairs. The dealer called me and wanted to buy it back; he wanted the engine. So I sold it to him for $400. As far as I know that slant six is still powering some irrigation pump out in South Dakota. I thought the car was really ugly at the time, now I wish I had it back!
In 1963, I bought the new, 1964 Dodge Dart GT with the floor mounted manual transmission. As I recall, we called them four in the floor at that time. It was a gas to drive. I really loved it, but traded it for the 66 Dodge Charger with the 383 engine. That was a car.