UPPER CONTROL ARM EXCHANGE QUESTION

There are some people with wrong information. Even some of the books that people rely on are incorrect.
Here is the truth:
ALL A body cars from 1963 to 1976 with 9"front drums used the upper control arm with the small upper ball joint.
ALL A body cars built through 1972 with 10" front drums used the same UCA and Upper ball joint as the 9 inch drum cars.

In 1973, a few things did change. The cars with 9" brakes were still built with the small upper ball joints. I have seen them. I have owned them. They are not unicorns or swap jobs, they were built that way. Every one of them I have seen was a slant six model with very few options.
Also in 1973, the cars were available with 10" front drums. The spindle/knuckles they used were different than the 63-72 model cars with 10" drums. These 1973-76 10" drum cars DID use the same upper control arm and upper ball joint used in the 1973-76 11" front disc cars.
I'm not trying to insult anyone here, just trying to pass on correct information.