A fuel pump includes a cam arrangement surrounding a rotor and disposed within a spacer ring. The cam arrangement is configured to deterministically translate relative to the spacer ring and the rotor during stroking of the pump. An involute gear set provides an interface between the cam arrangement and the spacer ring. In some cases, the involute gear set is configured to provide a linear translation of the cam arrangement along a timing line. In other cases, the involute gear set is configured to provide a linear translation of the cam arrangement at an angle relative to the timing line.