A system includes a camshaft disposed along an axis from a drive end to a opposite end, and the camshaft includes a plurality of journals configured to support the camshaft and is spaced along the axis. The camshaft includes a plurality of cams spaced along the axis, and is disposed along the camshaft in sets, where each set is disposed between a respective pair of journals of the plurality of journals. The camshaft includes a plurality of mass portions, where each mass portion is disposed between a set of cams and a respective journal. The plurality of mass portions is disposed along the camshaft such that a center of mass of the plurality of mass portions is nearer to the drive end than to the opposite end, and the plurality of mass portions is configured to increase a natural frequency of the shaft.