thanks, I will check him out

You might want to visit the forum at P15 D24.com and check in with member Jim Yergin.  He has installed rear disc brakes on his 40 Woody.  I don;t kow if he chaged the rear axle for a latter model or converted his stock unit.

http://www430.pair.com/p15d24/mopar_forum/forumdisplay.php?f=2

I have discs on the front. I don't know of any disc for a '47 rear.

Other than maybe cheaper wheel cylinders, "better" parking brakes (after adding the necessary cables and hardware, what advantage is there to the swap?  Perhaps being able to work with out a hub puller ( but that can be addressed on the current system).

Why not upgrade to discs???

I saw a how to do it article somewhere on putting the backing plate/brakes/drums? from a 70's MOPAR onto a 1940 and up MOPAR rear.? I don't remember what club newsletter the article was in. I had a copy of it and misplaced it. Does anyone know where I can find this article. I have my Plymouth Buletins from years back, the Inliners Club 12 Port News and the WPC News. It had to be one of those three.
Does anyone remember this article and know where i can find it?