Bleeding Brakes - 9" Drums

Is the dual port master cyl. for 4-wheel drum brake's? On a 4 wheel drum brake master cylinder, both of the fluid resevior's will be of equal capacity. What I'm saying is both resevoir's will hold the same amount of fluid.
If you have large/small resevoir master cylinder, that would be a disc brake/ drum brake master cyl. And last but not least, make sure your splitter block, down on frame rail, is for 4 wheel drum's. Hope this help's.