My 440 RRT/SE has disc in front, drum in back. Master cylinder has two wells, one is bigger than the other. The entire master cylinder is bigger than for drums all arouond. Note that Mopar is known for varying same part number among similar but different applications. My brake line fittings would not tighten down in one master, and I had to replace with a different one that had the cast fitting shaped slightly different so the line fittings would go down all the way and not leak. Part numbers all the same. With aftermarket and rebuild service, you might not know until you install and fill to check for leak.

Just did this two weeks ago, info is fresh 10/07
Steve Legel