clearance for clutch
 

Have 1953 flathead with speedway t 5 conversion. Clutch wont disengage. 10.5 in pressure plate and disc. Pressure plate is high performace 1800 lb. Did some measurements and have barely quarter inch clearance between trans shaft and raised center on clutch disk.Pilot shaft has plenty of clearance. Im thinking trans shaft is hitting clutch disk when pressure applied. Is there another clutch disk that would give more clearance?