Gregory then began to wind down his motor racing career, continuing to compete in international sports car races with some good results including a second-place finish at the 1966 1000 km race at Monza alongside John Whitmore.
Gregory comezou a relaxarse na súa carreira de automobilismo, continuou a competir nas carreiras internacionais de automóbiles con bos resultados, incluíndo un segundo posto na carreira dos 1.000 km. de Monza de 1966 xunto a John Whitmore.