Subaru introduces the EX40 overhead cam engine to its line of high-performance air-cooled, 4-cycle EX Series engines. The chain-driven overhead cam technology allows the EX40’s intake and exhaust valves to be positioned to offer lower resistance for the air/fuel mixture flow, according to the manufacturer, thus optimizing engine performance. Designed with an efficient pent-roof combustion chamber, the EX40 is able to utilize a high compression ratio to produce higher power and torque.