An electric cam phasing system is provided. The electric cam phasing system includes an electric motor including a center shaft; a camshaft; a center fastener extending into a center of the camshaft and a gearbox including a sprocket and a drive unit. The drive unit includes an input shaft coupling connected to the center shaft. The drive unit is configured for coupling the camshaft to the sprocket in a manner such that relative phasing of the camshaft with respect to sprocket is adjustable via the electric motor driving the drive unit. The electric cam phasing system also includes a lock positioned axially between the center shaft and the camshaft, the lock being configured for selectively engaging the center fastener to lock the gearbox.