 In 1956, Norton development engineer Doug Hele was tasked with creating a 500 cc overhead valve road-based racing machine to challenge the larger-displacement side valve 750 Harley Davidsons run in the same class at AMA-organised Daytona 200 races.Initially unsuccessful, the project was turned into creating a road-based race engine as a replacement for the ageing Manx Norton racer engine.Hele designed a lighter-weight, lower frame with slightly shorter wheelbase, based on Featherbed principles having slightly altered frame runs and shortened telescopic front forks which became known as "Lowboy".