 The main difference between the 600 and 750 classes are the restrictor plates, with 750 allowing more power.The 600 class is mainly for kids aged 10–14, and the 750 class is mainly for kids aged 14–18, or younger kids who have more driving experience.Both series mandate a maximum of 55% left side weight, with the minimum weight including driver for the 600 class being 680 pounds and the 750 class being 700 pounds.