 Complete the following phrase:  He sustained a concussion when he spun off track at the Nürburgring during trial runs for a sports car race held in May 1957. His Ferrari was destroyed. It was the only one of its marque to be entered in the Gran Turismo car class of more than 1600 cc. Von Trips was forced out of a Royal Automobile Club Grand Prix at Silverstone, in July 1958, when his Ferrari came into the pits on the 60th lap with no oil. The following August he was fifth at Porto in the 