Master Cylinder

As mentioned a disk/drum MC would work fine. They don't come w/ the brake rod. You will need a new rubber bushing for the rod tip to lock in the MC piston. Insure the dust bellows is already on since you only get one chance. But, I wouldn't fool with an old cast-iron MC unless you like the rusty look and leaking brake fluid, i.e. paint remover. Use a later 2-bolt MC on a 2-4 adapter plate. Many use one for a 1980's Dodge truck. Dr Diff and others sell them kitted, or you can buy just the plate on ebay ($30). I used an MC for a 95 Breeze ABS w/ adapter on my 64 Valiant and fit fine, but there are a gazillion alum 2-bolt MC's out there. Of course they are for front disks since that was standard 1973+. There is a single reservoir w/ 2 chambers. The lid seals tight so no fluid loss or moisture getting absorbed. You can even wire the low-reservoir switch to gnd, in parallel w/ your e-brake switch (and imbalance switch for cars w/ those, ~1969+). Any that switch to ground will light the dash lamp.