Upper Ball Joint Question

1WildRT said
Yup, small until 73 And in 73-76 if it has 9" drum brakes it still uses the small joint..

Basically if it use the 5x4 lug pattern it uses the small ball joint...

if it use the 5x4.5 lug pattern it uses the larger ball joint...

No.

All UCA's 73+ are the large ball joint style regardless of bolt pattern. The spindles and the brakes changed. 9" drums in the front also went away. Only the first few months of '73 production were different, by November '72 the changeover to the new 73+ drums was finished. So, large ball joints, small bolt pattern 10" drums.
https://www.hamtramck-historical.com/images/TSBs/1973/05-03-73C page1.jpg

70SwingerGuy said
I have a 70 Swinger, 340 4 spd and am unsure as to what size upper ball joint to get. Ive been looking around and have found both small and large size joints, and application descriptions can be confusing depending on supplier. And one supplier doesnt even list if its small or large, just that it will fit my car.
So what is the correct ubj for my car? I cant go out to the garage and measure cause its in the bodyshop right now, and Id like to take advantage of a boxing week special if I can.
Thanks for any help FABO!

Like RRR said, if it has the factory UCA's and brakes it should be the smaller upper ball joint. But a lot can happen in 55 years.