Abstract: A high-pressure valve assembly having a valve body that defines a preferably cylindrical valve cavity, a fluid inlet, a fluid outlet and a plurality of valve ports; and a fluid pressure intensifier assembly having a plurality of piston-plunger assemblies and utilizing the high-pressure valve assembly to distribute the working fluid. The valve assemblies have a valve rotor rotatably mounted within the valve cavity. In one embodiment, the valve rotor divides the valve cavity into a high-pressure region in communication with the fluid inlet and a low-pressure region in communication with the fluid outlet. As the valve rotor rotates, at least one and preferably three or more valve ports communicate with the power chamber and at least one and preferably three or more valve ports communicate with the discharge chamber.