KAD refers to Opel models in ascending price: Kapitän, Admiral and Diplomat. Less than 90,000 were built during their production run, which strikes me as being too few to be profitable, even if prices were high. But perhaps I'm wrong: Opel management decided to continue the lines with a B series form 1969 to 1977 (though Kapitän production ended sooner). Over this 8-year span, just under 62,000 KADs were built, continuing the pattern of low numbers on a model-year basis. Some background on the A-series Admiral (55,876 built) is here.
What interests me about 1964-68 KADs is how similar their styling is to General Motors' new-for-1964 Buick Skylark, Oldsmobile F-85 and Pontiac Tempest models. I'll focus on the Oldsmobile in this post (background information here).
I have no information at hand regarding who styled those Opels. In those days GM sent some of its design personnel to Opel, including the man who would be in charge of Opel's styling group. So one could argue that was how Detroit design concepts also appeared in Germany. But there are details on 1964 Oldsmobile F-85s and KADs that are so similar that I wonder if parts or tooling or some of each crossed the Atlantic. Knowledgeable reader comments are most welcome regarding this.
It also needs to be mentioned that these cars were fairly similar in size. KAD cars had a wheelbase of 112 inches (2845 mm) and were 194.8 inches (4948 mm) long. Oldsmobile F-85s had a 115 inch (2900 mm) wheelbase and their length was 203 inches (5200 mm).