K-frame alignment?

LCA pivot and bushing
I replaced the bushing not long ago, mile-wise. I rebuilt the entire front suspension when the 400 was in it.

I probably should have welded up all the seams but other than that there is no obvious damage to the k-frame.

You do what you like, but I wouldn’t be driving that car on public roads until I had an explanation and/or solution. The amount of issues you’ve had suggests something significant is wrong, and not the kind of thing you want to find going down the road at speed.
It drove fine at speed with the 400. Many times. No weird tire wear, no pulling, no vibrations. Nothing.