Hmm, not sure I understand. The 10" drums and 10" disks do use the same size master cylinder bores.
The master cylinders themselves are not the same though, disk/drum masters have a larger reservoir for the disk circuit and and a different residual valve pressure for the disk circuit as well. I guess I didn't make that part clear, a 15/16" drum master cylinder isn't the same as a 15/16" disk master cylinder. Is that what you meant?
