Master cylinder question

[Maxhr190]

I am in the middle of a Scarebird front disk conversion for my 66 D100, I purchased a 72' Dodge W100 m/c as suggested by Scarebird. I know there should be one reservoir larger than the other for disk/drum, the one I received from Napa looks like a disk/disk as both reservoirs are the same size, however one port is 9/16" the other 1/2" why is that? is the difference in the cylinder ? Thanks

[kurt]

It should have a large and small resivoir. Its a drum drum . Exchange it for the right one.