The rear drums on KF products can be very difficult to remove. The combination of a tapered axle, 160 ft lbs of torque to hold them in place, and age all spell trouble years later.
First, be sure your car has the one piece hub and drum. Some had drums not attached to the hub...like a modern car...so the hub will stay in place but the drum comes off. If yours is the one piece, using the right puller helps. The correct unit attaches to the lug nuts/bolts (47s should have nuts like modern cars) with a post that seats on the axle. One thing to note, remove the axle nut, turn it around and thread it down to where it's flush with the end of the axle. That will prevent splaying of the axle end.
From there, it's just brute force. You need to overcome the surface tension the drum is exerting against the axle. Sometimes some heat will help, just be careful you don't melt the axle seal. Another trick is to spray some Automatic transmission fluid into the space where the two parts are making contact. I've found it to be an excellent lubricant as it's thinner than oil and will get into tight spaces.
Leave the puller on the assembly as tight as you can get it. If the drum won't budge, a sharp shock with a heavy hammer on the puller end or arm (depending on which you have), every now and then should eventually do the job.
