Need master brake cylinder help

[silver fox]

I need a mc for the 73 duster the car is in storage now what info do I need to get the right one it's drum in back dic's front thank's

 

[4spdcuda66]

Try here. Power or manual brakes? /6 or V8?

http://www.rockauto.com/en/catalog/...+cylinder,1836?a=Referer+www.google.com+URL+/