72 stance

[oldcarnut]

Thanks for adding me to the forum and this is my first post but I've used the info. lots spread out throughout the site. This is my 72 I bought recently. It's had some issues I've worked on and I just had all the coils springs replaced to help (I thought) the stance and lean. Now I'm wondering if it has been warped some considering the plates welded on the frames. Wondering if anybody had any thoughts about what to look at next to get it somewhat straighter. The bed is lower on the drivers side as the pic shows from the rear and there is a about 1 1/2 difference in tire to fender well height. Each side has these plates cut out and welded on the frame as shown. Why Im not sure unless it was to correct a twist or provide extra load capacity. Any ideas?