Ford Sierra RS500 Cosworth Diamond WhiteFord took the decision to build 500 extra RS Cosworths late in thelifecycle of the car because Group A saloon racing rules allowed500 evolution examples to be built to homologate a more extremespecification. Thus, between November 13th and 24th 1986, Ford’splant in Genk, Belgium, made a batch of 500 Sierra RS Cosworths,which were stored at Dagenham until a specification was finalised.They were then converted by Aston Martin Tickford in Bedworth,Coventry, between June 18th and July 28th, 1987, who fitted a largerGarrett AiResearch T04 turbocharger, a ‘flip’ on the rear wingand that distinctive RS500 badge