Strange 1964 Valiant

[COPO_Anders]

Yesterday a friend of mine told me his father in law had an unusual 1964 Valiant. I believe he said they were not sold as Plymouth cars over here. Instead they called them Chrysler Valiant, with different emblems than the ones used in the U.S.
The seats were reupholstered fifteen years ago but otherwise the car looks pretty much the same as when his father in law bought it. There is one detail in the second pic that should get your attention. And remember, this is a slant six car.
So, what is that detail I´m thinking about ?