Replacing Master Cylinder

i just replaced a 2225541
got a 15/16 bore from autozone lifetime warranty for 55 bucks
glad i want smaller then the 1 1/8 15/16 great pedal feel
it was a bolt in
Hope you saved it. Even if it needs a rebuild, some one will want it.

Here's the M/C you're looking for.
Note the casting number on the bottom 2225541. According to the link to the article Steve posted in #3, this is what you need. Be aware that the original version of this article had a typo, with the incorrect number shown.
Also note the flat machined front with no "snout" like the one pictured in post #4.
These are pretty expensive, but could be your best bet if you want to have the correct appearing one. Quite a while ago, the best price I could find for a rebuildable core was close to $200.

NOS Brake Master Cylinder 67 68 69 70 Dodge Dart Custom Swinger w/ Front Disc | eBay
Yup. That's Kanter. They must have a small stock of them. I'd have to check what I paid but they may have slowly been bumping up the asking price on them over the past few years, but that's it. Pretty much a Chrysler p/n 2808600 without the tage and painted bail. Best we can tell its a Bendix for Chrysler that prob never went to Chrysler but into the replacement market.