A valvetrain assembly has valves each having a valve stem; a main camshaft with main cams, a main cam corresponding to each valve; main rocker arms each corresponding to a valve and having a valve stem actuation portion, a pivot axis parallel to the main cam shaft, and a main cam follower for following the corresponding main cam, wherein the valve stem actuation portion, pivot axis, and main cam follower are arranged along the main rocker arm length distanced from each other; an auxiliary cam on the main camshaft; an auxiliary cam follower for each auxiliary cam, following the auxiliary cam, wherein each auxiliary cam follower is movable on one main rocker arm between a first and second position; a latch on respective main rocker arm(s) for locking the auxiliary cam follower in the first position; and an auxiliary camshaft with a selector cam for each latch, controlling the latch.