 Callaway supplied the development, testing, and subsequent production turbocharger systems to Kohler.In 1990, Renzo Rivolta's son, Piero, asked Callaway to be the engine supplier to his new Iso Rivolta Grifo 90, a revival of the Iso Rivoltas from the 60's and 70's.The Iso Rivolta cars had DNA that included Italian coachwork and V8 engines from Corvette – an inspiring formula for many.