Mopar tapered axles can they be swaped?????

I have a Aussie 62 crysler royal I'm messing with for my wife. Does anybody know if the tappered axles can be swapped for straight axles in a similar method like a early ford rear. The diff looks like a 8 3/4 with the round pumkin.It's about 60inches wide from drum face to drum face I think the chassis is based on a 56 plymouth with poly power. I want to keep the earlier style centre but lose the tapered axles and do a break upgrade.

 

Go to www.autohobbydigest.com and look up 8 3/4. There is a tonne of info there.