An open deck engine is a type of engine block design where there is an open channel between the cylinders and the engine block walls. This design is commonly found in lower horsepower aluminum blocks and is the easiest to manufacture, providing the overall best cooling efficiency due to the coolants ability to make full contact with the surface area of the upper portion of the cylinder. However, the downside to an open deck is that it provides the least amount of structural support at the top of the cylinder walls, where they need it most, making it the least reliable choice for almost any type of forced induction or nitrous application. Open deck engines are usually used in low horsepower aluminum blocks and are less expensive than closed deck engines.