The 1937 Indian Four can be directly credited to the genius of William Henderson whose pioneering efforts embraced the four cylinder motorcycle design in America, first with his namesake Henderson motorcycle and later, the sporty Ace from Philadelphia. The Indian Motocycle Company purchased the credit strapped Ace Motor Corporation in December 1927, and immediately began to market the famous Ace in their familiar Indian Red finish. It didn’t take long for the new owners to standardize their acquisition into the family of Indian motorcycles, using inventory from the Scout line to make the first true Indian Four. In a daring engineering and marketing move for 1936, the Indian Four reversed its intake and exhaust valve position, placing the hotter running exhaust valves on top of the motor to place them in the cooler air stream. Unfortunately, this also placed the engine heat closer to the rider’s inner thigh. Thus was born the ill-fated “Sport Four”.
