Good catch on the front seats, I saw that pattern in the bottoms but didn't notice that the tops and rears were different.
Trying to learn, not to start an argument:
Agreed that 71-up went to single-diaphragm, but this car's doesn't look like the type I've seen on 71-up disc cars, which is this one, with a pocket where the MC mounts and a forward-facing crimp. I now notice the MC on the FS car looks like same-sized reservoirs, which suggests a drumbrake MC too?
View attachment 360199
One on the left below is the 'slabside' drumbrake booster with the screw-clamp and a pocket where the MC mounts, the righthand looks like what I've seen on drumbrake Fuseys? And kinda resembles the one on this car due to the orientation of the crimp? Or does the FS car have some aftermarket will-fit booster for discs?
View attachment 360200
We are here for the same reasons, no issue at all. Here is what I can do to help the dialog based on what boosters are on my cars that range from 1969 to 1973 that are unrestored vehicles......
This is what I believe to be the original booster on my 1970 Chrysler 300 with disc brakes (80K miles) - dual diaphragm
And this is from a second 1970 Chrysler 300 also with disc brakes - this one is a rebuilt booster using the original booster (205K miles) ...............again dual diaphragm (side note - this is my avatar car that I had with me when I worked for Chrysler in Detoit, but never drove it in the winter and it was always garaged. It is probably one of my most treasured cars since I have many memories driving this car all over the country - I bought it used in 1972 at Birmingham Chrysler just north of Detroit with 29K miles on it)
And this is an original brake booster from one of my 1971 Chrysler 300s, also with disc brakes (80K miles) larger diameter single diaphragm
This is another 1971 Chrysler New Yorker also with disc brakes and its original brake booster (36K miles)
This is an NOS replacement booster for my 1971 Chryslers - I ordered 5 of them and this is what they sent as a factory replacement for all 5, some of which were ordered at different times......
This is a factory original brake booster on my 1973 Monaco with disc brakes, and note that it looks like the NOS booster that Mopar sent as a replacement for the factory original comparable 1971 booster (80K miles).....this leads me to believe this is the booster that the factory put on the disc brake cars starting with probably the 1972 models (I do not own any 1972 C bodies).
And this is the booster that appears original to my 1969 Chrysler 300 with 70K miles and factory drum brakes. Visually, it looks like a smaller diameter than the single diaphragms on the 71 and up cars.
In looking at the information available on the car at hand in this thread, it appears from the window monroney that the car originally came with factory heavy duty drum brakes with (B51) power assist.
In looking at the brake pedal on this car, it appears to have a disc brake pedal dress up surround, so I would guess it has been converted to factory disc brakes by an owner of the car, including the appropriate pedal that would go along with it. Accordingly, the owner did install the correct disc brake master cylinder and must have ordered a replacement brake booster and was sent one that is the same as for my 1971 and up C bodies when ordered as replacement from Mopar for 1969 and up C bodies with disc brakes.
This hopefully will clarify things on an issue that confused me for some time too.
Now in going forward to restore my vehicles, I face the question as to whether to just have my original boosters replaced or use the factory replacements that mopar supplied.
One of the tougher questions I face in life.......................
