Bad products built by vendors that don't care
We have a 1950 Shoebox Ford here in the shop that a nice customer was trying to assemble himself at home. He doesn't have any experience doing this sort of thing, but figured he had enough mechanical ability to do it on his own.
That is, until he started getting issues with parts not fitting well.
The one part I found particularly frustrating is this Steering Improvement Kit available through a few sources. It uses an AMC Idler arm and fabricated center-link to try and remedy the inherent bumpsteer with these cars. And by the looks of it, it would make that situation better.
HOWEVER! It creates a whole new problem. The tie rods hit the idler arm and pitman arm well before the suspension bottoms out. It's damn near touching at the lowered ride height, and if you steer it, the problem becomes severe.
We have tried to reconfigure this a few different ways. Even to the point of moving attachment points to make the installation even better. But after reading a few blogs around the internet, this seems to be an issue that has come up and the manufacturers don't care.