won't go in gear

Ok hear is something else to check, my buddy was changing the clutch in his daughters 340 4spd Demon with a new Centerforce and ran into the same problem it was driving us all crazy. We found that centerforce had changed there pressure plates a few years back and put ball bearings between the hat and the diaphragm spring for smother operation. Well a few of these bearings had dislodged, giving the clutch an uneven disengagement dragging the disc. I had an older centerforce hat in good shape, put it in problem solved, sent other one back for refund.