1959 B46 Brake chamber size & differential

[Keith S]

I'm rebuilding a 1959 B46 and have some brake questions.

1. Brake chambers: I have Type 12 on the front (5-11/16" dia.) and Type 30 on the rear (8-1/8"). Is this a common configuration?
2. The rear chambers are mounted on two different cast brackets - one cast iron, one cast alum. They are different shapes. I'd like to replace the right (alum) to match the left (iron). Or...
3. There are chamber brackets welded to the differential. Looks like I'd need a lot of parts ($$$) to move the chambers to these bracket. 

And ... some additional photos.

 

Edited December 8, 2016 by Keith S