Upper ball joint measurement

yes, 73+ ball joints are larger. the hex (square), the thread and the tapered shaft are all larger.

how do you know if you have big joints? measure the hex (square)

we covered this before:
[WANTED] - 1973 to 1976 upper a arms

now, that being said, these cars are 50+ years old and anything could have been swapped in there. so just because you have 74 pieces, verify they are in fact the correct units.