In one form a rocker is disclosed coupled with a valve stem at one end and a cam follower at the other end. The rocker is operable to rotate about a fixed axis. In one form the cam follower includes a set of lower rollers operable to follow one cam lobe and an upper roller operable to follow another cam lobe. A leaf spring can be used to couple the cam follower with the rocker. A cam shaft can have a nested configuration including an inner shaft, an intermediate tube, and an outer tube. Cam lobes can be fastened to the cam shaft in one form by fastening through each of the inner shaft, intermediate tube, and outer tube, and in another form by attaching at least two devices inserted from either side of the cam shaft and that are not inserted at least through the inner shaft.