A power steering system for a marine steering includes a hydraulic cylinder, an actuator block that is mounted on an outer end of a ram of the cylinder, and valving. An actuator arm, mounted on the actuator block, is connected to the steering link, to the steering rod, and to the valving. The actuator arm is configured to move on the actuator block upon the transmission of steering command forces thereto by the steering rod to actuate the valving so as to drive the ram into or out of the barrel and to transmit steering forces to the steering link from the actuator block. The actuator block is configured such that it can accept standard steering links of different engine brands.