upper control arms

A ‘69 Barracuda came from the factory with small ball joints

A-body upper control arms are unique to A-bodies, they will not fit B/E/F/M/J/R or C bodies, and none of the upper control arms for those cars will fit an A body

All A-body upper control arms were large ball joint staring in 1973. They were the same as the 67-72 A-body upper control arms except for the large ball joint

Sounds like your ‘69 Barracuda was converted to 73+ controls arms, spindles and brakes at some point. It’s a popular conversion to get the 5x4.5” bolt pattern and later disk brakes.

The full article with the spindle geometry information on the FMJ spindles is here

https://www.hotrod.com/articles/mopp-0503-swapping-a-and-b-disc-brake-spindles/