a variable ratio rocker arm is provided for use in combination with the valve stem and push rod of an internal combustion engine . the rocker arm has an elongated slot defined between a rod seat and a toothed rack . a fulcrum rod is provided with a toothed sector and a curved sector , with the toothed sector being engaged with the toothed rack portion of the rocker arm . a roller bearing assembly is movably disposed between the rod curved sector and the rod seat , with the roller bearing assembly being rollable along the rod seat . an actuator arm is coupled to the fulcrum rod for simultaneously rotating and translating the fulcrum rod through the rocker arm slot . the operating arm causes the fulcrum rod to rotate and translate along the mating toothing from one point of pivotal engagement , corresponding to a first engine operating condition , to another point of pivotal engagement , corresponding to a second engine operating condition .