Can i use existing parts on my 84 4 wheel disc car to convert a drum axle to replace my axle? I found a good replacement for my broken axle but it is a drum setup.

 

THe flange that the backing plate mounts to is completely different between a drum and disk rear. I doubt you can swap much of that over. But maybe you can take them both apart and make one good disk one out of the 2, depending on what's broken.