what to do?, upper b/j loose fit

Same in my 64 Dart. The original factory ball joints weren't screwed into threads, but rather cut into virgin metal, thus they often take some metal out with them. The factory spec is something like 135 ft-lbf to install, which is OK the first time, but would probably chew up the UCA the 2nd time. One side wouldn't tighten in mine, so I removed the UCA, tack-welded it it in and re-painted. Actually, I was re-using the original ball joints (not worn) and had just removed them to purty up the UCA. The upper ball joints may last forever if you keep them lubed and replace the boots. I don't see the uppers carrying any significant force, they just help align the wheel.