Subaru EJ Series Engine Closed Decking ServicesOur deck closing service involves machining the top plane of the engine case (the head plane) to accept CNC machined inserts. This process fully supports the cylinder walls at their weakest pointthe top, where combustion occursensuring they withstand the intense pressure when the engine is running. Additionally, all coolant bores present in the head gasket are precisely machined into the cylinder supporting inserts, ensuring the engine's cooling