Input (grade 13): Bugatti, Duesenberg, Alfa Romeo, Mercedes-Benz and Miller built successful racing cars with high-performance dual overhead camshaft straight-8 engines in the 1920s and 1930s.
Output (grade 12): Bugatti, Duesenberg, Alfa Romeo, Mercedes-Benz and Miller built successful racing cars with high-performance straight-8 engines in the 1920s and 1930s.