My guess is these arms are actually earlier Mustang type that fit the 1" shaft sectors, will probably be in the parts system for years...
Just call up rare parts an speak with Glen.. he knows the issue and will take car of you.. he ended sending me the correct one even though I bought off that POS Just Suspenion....
I talked to Leslie at rare parts this evening and she is going to call me back in the am to sort everything out. I will be sure to tell her that Glen has dealt with this before. Thank you for the post. It has helped in a huge way.
Received my replacement today and it's a perfect fit. The people at rare parts were easy to deal with and extremely helpful.