Okay, when you said "big" center nut, my mind went to front drums that sometimes are difficult to remove because shoes are stuck to inner brake surface or there could be a ridge cut where the lining on shoes will not come over. On the rear drums, as others have mentioned, some will come off the tapered axle easily, while others will not budge unless you have a KR Wilson or equivalent type puller. I recently posted pictures on another thread of a KRW removing a drum that would not come off by any other means I had tried. Sometimes you must have the correct tool to get the job done, and in this case it is very important.
https://www.fordbarn.com/forum/showt...ight=KR+Wilson