What i found is that the XRF PN is actually the same PN as moog PN except it has the the prefix "XRF", a space, then the moog PN.
I believe the numbers are correct for these which are the LH and RH A body lower ball joints. I believe. But could be mistaken that these are the same for all A bodies from 1963 to 1976. I would check mine, but everything is boxed up and sitting in the storage loft above my shop until i get ready to reassemble the front end. Plus mine is a frankenstein of sorts. My setup is 74 A body spindles , cordoba big brakes, tubular uppers from dillinger, and boxed 74 valiant lowers with factory sway bar tabs. So i went with uppers and lowers that would work with 1974 spindles and 1974 lower and upper arms.
The upper ball joints definitely were different. Smaller joint from 63 to 72, then went to the larger B and E body upper ball joint from 73 to 76.
I suggest you do some online research thru maybe rock auto to get the moog PN , then go to www.mibearings.com add the XRF prefix followed by a space, then the moog PN.