I don't know if there is a Kit available, but I would use a 67 Master cylinder for a Drum Brake car (67 was the 1st year they had a dual master cylinder, and the 1st year for optional disc brakes so make sure you don't get a disc brake master, also make sure it is for Power or manual brakes, same as your car.) Then change the proportioning valve to a 67 drum style, and run the needed extra lines.
I have only seen kits for disc brake conversions, and the only car I swapped in a dual master cylinder with out converting to disc's was a 66 Lemans. That is how I did it. required a lot of tube bending.
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