An overhead valve (OHV) is a type of engine design where the valves are located in the cylinder head, above the combustion chamber. This configuration allows for more efficient airflow into and out of the engine, improving performance and fuel efficiency. OHV engines typically use pushrods to operate the valves, which are connected to a camshaft. This design contrasts with older engine types, such as flathead engines, where the valves are located in the engine block. The overhead valve system is commonly found in many modern vehicles, including those made by Ford and Chevrolet, due to its advantages in power and efficiency.