When I rebuilt the front suspension of my 69 I ran into a problem. When I pulled the cotter pin on a lower ball joint the nut and the tapered shaft were both turning. I thought the tapered shaft had loosened at some point before I owned the car. I had to split the nut to get it off. Well it wasn't until I went to install a new lower ball joint that I realized what the problem really was. The ball joint mounting hole was bigger than the new ball joint. I compared the old ball joint and found that not only was it bigger but the tapered shaft was completely different. It hadn't come loose, it never fit correctly in the spindle arm. Luckily I was converting to discs and was putting in new spindles. I got a new A arm at an E-town swap meet for $10. But what car uses that A arm? Everything matches a 69 except the ball joint diameter is bigger. If you know you can have a free A arm.