In 1967, Aermacchi redesigned the aluminum cylinder and head of its 250cc four-stroke overhead-valve engine, leading to an 18 percent horsepower increase of the Model H Sprint. The H sprint also got a new, quieter muffler, a new taillight and a 5.1-gallon road-racer-style gas tank. It weighed 273 pounds. Records indicate Aermacchi-Harley-Davidson produces approximately 2,000 of the Model H Sprints in 1967.