Im using the techexams and mike meyers passport to study and found a conflict;
Techexams (techexams.net/technotes/cpu_sockets.shtml) says that the K5 and K6 processor have 321 pins.
Mike Meyers Passport (page 80) states "AMD K6 series of processors had a 296-pin PGA form factor" also "The K5 processor had a 296-pn PGA and used a socket 7".