Valve question

I'm doing a drum to disc conversion on a 73 Dodge Dart. The spindles and everything I got are off a 73 or 74 Duster... My question is, the prop. valve on my Dart looks exactly the same as the prop. valve that came off the Duster. I figured they would different on a drum brake car than a disc brake car. Is it internaly different or did they use the same valves on both. I have a pic of the one that came off the Duster.