A surgical instrument. In one form, the surgical instrument comprises a first jaw (1520) and a second jaw (1560) that is movably supported relative to the first jaw for selective movement between open and closed positions relative to the first jaw. A firing drive shaft (1610) is rotatably supported in one of the first and second jaws. A firing member (1620) operably interfaces with the firing drive shaft for selective axial travel in response to rotation of the firing drive shaft. The surgical instrument further comprises a distal power shaft (1130) that is separate and distinct from the firing drive shaft and is configured for selective operable engagement with the firing drive shaft. A closure member (1410) is supported for axial travel on a proximal end portion of the first jaw and is configured for selective threaded engagement with a portion of the distal power shaft.
