Abstract: In a valve actuating system for a multicylinder internal combustion engine having a camshaft supported in bearing pedestals on the cylinder head of the engine with rocker arms pivotally supported by rocker arm support shafts also mounted on the bearing pedestals and coupling levers arranged adjacent at least some of the rocker arms and including hydraulically operable coupling devices for engagement with the adjacent rocker arms, at least one of the bearing pedestals includes a pressure control space to which oil under pressure is supplied and the rocker arm support shafts have internal fluid flow passages in communication with the pressure control space and with the coupling devices so that pressurized fluid can be admitted to the coupling devices under the control of valve means disposed in the bearing pedestal.