Here's direct to a picture of the combo valve:
page 8, 1970 Master Technicians Conference Brake Hydraulics 1970 can get confusing with all the variations.
The illustration also shows the metering valve, which was not used with the a-body K-H fixed caliper system. On the next page is a chart that indicates which disk brake systems got the metering valve. (The metering valve is to create a slight delay on the front brakes)
1972 illustration is clearer:
http://www.imperialclub.org/Repair/Lit/Master/293/page13.htmSame combo valve for A-body disks as '71 and '70.
Those booklets explains all of the valves and the 1970 booklet has a list of master cylinders on the back.
P.S. Two good resources for factory info not in your service manual or parts book:
http://www.imperialclub.org/Repair/Lit/Master/index.htmhttp://www.hamtramck-historical.com/(go to the library)
