Wanted: Upper ball joint socket

I am converting over to later model discs and noticed that one of my upper ball joints isn't screwed down all the way, there is still about an 1/8 inch gap before it bottoms out. I bought the a arms from Master Power with the ball joints already installed. I am hoping that I can just tighten it up and that the installer didn't strip the threads.

Does anyone know if the local auto parts places that loan tools carry anything for our older cars? Does anyone in the mid west have a socket I could borrow? I'll pay shipping both ways and throw in a little change for your trouble.