Two years after initially posting this page, I've found a Honda 600Z diecast and built an HO version resin body mounted on a shortened version of the SlimLine chassis.
598cc of aircooled vertical twin power! Top speed, indicated 80mph with a tailwind. With a head wind, about 45mph! My car, the second car I owned, was blue...I'd like to resin cast this...anyone seen a diecast? ...Tom