Brake master cylinder

[geasson]

Well, it is running. Rough but it is running. It has no brakes and fluid is leaking out the back of the master cylinder and leaking on the inside. I suspect a new master cylinder is needed or at least a rebuild kit. My issue is that I have the rectangular master cylinder and according to the catalogs, a 1966 should have a round master cylinder. Did the PO change to an older master cylinder or did the 1-tons continue using the rectangular master cylinder. Which one should I buy???