Maserati, and Bugatti.

The 750 kg formula lasted until the end of 1937. By then, the German cars had over 600 hp, more than twice the rule makers had expected to be possible with that weight limit. For 1938, a new formula was introduced, limiting also engine sizes. Cars with a supercharger were permitted to have an engine size between 666 cc and 3000 cc, whereas normally aspirated cars were allowed