Alan, can you elaborate further on Mr. Katayama's involvement (and lack thereof) with S30 development?
Katayama wasn't an engineer, designer or even a 'stylist'. He had no real ability to give technical input on any of Nissan's products, and he never had any remit to do so anyway. He wasn't any kind of product planner. His education was in economics, and he joined Nissan to work in their nascent advertising and sales department. He was related to Yoshisuke Aikawa, Nissan's creator and first President (a fact which helped him all through his career...).
Katayama came into the story of what would become the S30-series Z when it had already started. His 'input' was more along the lines of "I can sell this" than any other measurable practical sense. He added the weight of his support for the 'Maru Z' team, which would have been a help to them when dealing with higher management, but the Z certainly had no details that can be attributed to Katayama's hand. He was living and working in the USA for the whole time that the S30-series Z was being created, and only visited Japan for short periods. He was a supporting cast member with a walk-on part, not a main player.
I've heard comments made he was 'banished' to the US...?
You've heard the phrase "Poor me, poor me, pour me a drink", right? He was actually given a promotion. Part of Katayama's schtick was to paint himself as a bit of a victim who had a constant 'battle' with upper management. If you think about it, this works well when talking to dealers; Enabling him to become the smiling, friendly face of a giant, all but faceless corporation. Good for sales. Good salesman.
He was an important figure in Nissan's history, indeed a great man, but so much garbage is written about him. Check out the very first paragraph of his Wikipedia page for example: It says he was "the first president of Nissan Motor Co USA", which is utter nonsense. The Wikipedia article goes on to contradict itself, and link to a classiczcars.com thread that I participated in: http://www.classiczc...youtube-video/
In his later years I believe Katayama himself started to believe the things that people were (mistakenly) thanking him for. He's on film saying "I designed it" (the '240Z'). I myself attended a small gathering in Tokyo where he was the honoured guest, and heard him say much the same thing. He made a long speech where he used the word "I" many, many times. Other members of the 'Maru Z' S30-series Z design and engineering team were in the same room, so he would have been better advised to say - at the very least - 'we'. It didn't seem to cross his mind. I felt embarrassed for the 'Maru Z' team members, but they took it all with good grace.
Catch me on a bad day and I might be tempted to say that Katayama's greatest sales success was selling the concept of "Mister K.". That's not necessarily a criticism, maybe more a wry observation on the cult of personality that surrounded him and the fact that he himself started to believe his own press...