Does that 9.25 bolt into a Mirada?
I can't find my dang book now but If I remember right when I was looking 3 years ago the spring perch width on a cordoba/late B was like 47" give or take.
I think on the earlier B's like 1970 it was more like 45". E bodies and C bodies had their own dimensions. I think C body was 2" wider.
I might have my F/M/J dimensions backwards with which era it matches to. I am not an expert on the 80's cars. I suggest a 9.25" because I think they were available on gov't cars and are otherwise laying all over the place. Dana 60's for a Mopar car are expensive, and I don't think there is much else outside of trucks to find them, which obviously everything will be too wide then.
You can measure your spring perch distance, if it is closer to the 45 then the 47 then your best bet might be an 8.75" from a 1970ish car, unless you don't care about the 4 grand price tag of a Dana. If it is closer to the 47" a 9.25 out of a Cordoba should bolt in.
The other thing about 7.25/8.25/9.25 is the driveshaft length is the exact same, an 8.75" needs the shaft shortened a bit to be correct. I am sure a Dana would need adjustment also. Brakes swap from 8.25 to 9.25 also so you can skip that expense altogether maybe.
Sorry I am not giving definitive answers for you, but double check all this before you pony up for a Dana
that's a chunk of change to find out it won't fit without an overhaul. I will keep trying to find my book for my Monaco project, I had this nifty pictogram with the dimensions in it, showed flange width, spring perch, and axle center to u joint length(driveshaft). Maybe someone else has that handy to, I think it was published in a Mopar book.....
