Description Available in: These highly modified vehicles, which can run under seven seconds at more than 195 mph, feature a purpose-built tube chassis and a lightweight, aerodynamically enhanced replica of original bodywork. The class features a wide variety of makes, models, and engines, including V-Twin entries from Harley-Davidson and Buell and inline four-cylinder-equipped Suzuki and Kawasaki models. To ensure a level playing field, pushrod-equipped V-Twin engines are limited to 160 cubic inches, and the high-winding four-cylinder engines cannot be larger than 101 cubic inches. Fuel injection is permitted, and spec gasoline is the only fuel allowed.