Back when lots of the taper axle Mopars were still on the road, I replaced every one of those rear ends when it came time to do brakes. I watched my boss, with lots of years experience with those axles destroy one of the axles on two different cars attempting to show me how to remove the drums. He had the proper tools, the proper equipment, and lots of experience. Back then you could easily find a 66 -70 8 3/4 rear end for $50, even then you couldn't buy a new drum that cheap.
Prices of this stuff isn't cheap anymore, but I would still swap out the rear end before I'd fight with the stupid drum/tapered axle drum removal more then 10 minutes. Loosen the nut, drive the car around the block. if it hasn't popped apart, its gone. Solves the rear trunnion as well.
Nothing wrong wit the ball and trunnion setup. Other than it being "different" than what most are used to and more expensive to make. I have broken more U joints than I ever did a B&T and I don't even want to talk about CV joints. Heck, I twisted the front yoke of my driveshaft in the 72 Dart.
Never had a tapered axle I couldn't get apart, but it can take time and patience. Something a garage may not want to deal with. Last time I took off the 51's rear drums I got the driver's side off easy. Pass side I had to let sit over night under tension after wearing myself out beating on the puller handle with a 5lb sledge. A couple of whacks the next morning and off it popped. If it hadn't popped that easy i was going to get out the 10lb John Henry sledge, lol. Never tried the antisieze thing since the FSM says to put it together dry, I had an oldtimer buddy that had sheared the key more than once back in the day. Not sure if antisieze had anything to do with that but a second key added to the joint fixed that issue.
