Many people perceive that all the parts are the same and any auto supply can get them, which is about 45+ years out of date. Even back then, the power disc brake boosters would probably need to be ordered, too.
The main issue with fitment is the diameter of the booster body, plus its "dual-diaphram" length issue (also related to the factory disc brake option). Plus the mounting plate possibly having different spacing than anything newer than possibly 1978?
As mentioned, the best option is to get the orig booster rebuilt by the above-mentioned company. The wait will be worth it.
Nice looking car. I always thought the Chrysler fuselage wagons were some of the best looking wagons ever made, back then. One great "aero" design, front to back. Only thing close was the similar-year B-body wagons.
Enjoy!
CBODY67