The Centerforce is a diaphragm type clutch disc with the added benefit of moveable weights on the "fingers" to assist with weight balance at higher RPM. The stock OEM was a 3 finger Long Type. The OEM clutch would load the pedal pressure as you added heavier duty clutch units and had a nasty habit of wearing out (or breaking) the pot-metal bushing under the dash - it only had a plastic, anti-friction liner. Initially we went to pillow-block bearings for the clutch shaft, but the Centerforce design made that less necessary and is a lot easier to drive with.
jim