A system for varying actuation of a combustion valve in an internal combustion engine, including a control shaft pivot housing fixedly disposed on the engine, a control shaft pivotably disposed within the control shaft pivot housing and eccentrically fixed to a control shaft disc, an input rocker subassembly pivotably disposed on the control shaft disc and having a contact feature disposable as a follower against a camshaft lobe, an output cam subassembly pivotably disposed on the control shaft and engageable by the input rocker subassembly and including an output cam profile for engaging a finger follower of the engine, and a bias spring to urge the output cam subassembly toward the input rocker subassembly. In one aspect of the invention, high lift events with full duration are produced whenever the control shaft is aligned such that the input rocker pivot center and the output cam pivot center are coincidental.