I remember last year on Trade Me there was a red HT350 for sale, and it was this car-even showed pics of it.
I worked at Paine Motors, Otara in the early 70s and remember him coming and going seeing Brian Wilson there.
I saw the green one he raced at Pukekohe- he had written HOHOHO on the bot lid.
Dont remember the brown one racing.
This was the standrd production saloons.
Had a quick look at my Motorman mags, but nothing there.