Front end wont stay aligned

Another place to check is the upper frame where the UCA mounts to and the cam bolts go in.
They are known to rust through there around the mounts and the top of the frame between them. It's a perfect spot for dirt to accumulate there and trap moisture for years causing the rust out.
I have seen that on quite a few cars.
Actually, a friend of mine had the same problem a couple of years ago with his Demon and had to dig a little deeper to find this problem.
Yes, it was bondoed up by the previous owner to hide it. Pretty scary.......
We sectioned in a new frame rail from a good car to repair it.