An apparatus for shaping plastic preforms into plastic containers, including a plurality of blow molding stations which each have a cavity in which the plastic preforms can be shaped into plastic containers. The blow molding stations are arranged on a movable carrier and each have a stretching rod which stretches the plastic containers in their longitudinal direction by a movement in a stretching direction. A fluid-actuated drive device is provided for driving the stretching rod in the stretching direction. The apparatus includes a guide cam which is arranged in a stationary manner and by means of which the stretching rod can be moved counter to the stretching direction as a function of a movement of the blow molding station. At least one portion of the guide cam is adjustable and, for example, by virtue of this adjustment a dependency of the movement of the stretching rod on the movement of the blow molding station can be varied.