The Caterham supplied 1600cc 8 valve Vauxhall is code C16NZ2. It was fitted to some Vauxhalls from around 1992 but is apparently quite rare. Caterham ported the head, threw away the injection gubbins and bolted on twin Webers instead. My car has been rolling roaded at 102BHP and is fairly typical of the other cars on the Classic Graduates grid. They all seem to have slightly different characteristics, presumably due to being hand ported and the setup of the carbs. There are certainly some engines that are slightly stronger than others. Some are relatively revvy whereas others have solid low down torque but a weaker top end (like mine). The engines are becoming harder to come by so if anybody is ever upgrading and thinking of selling their engine please let me know as the Graduates racers are always after them. They are remarkably reliable but the cars are now a minimum of 15 years old so we inevitably have a couple fail each year, and replacements can be hard to source.