Anyone ever try to swap a rear sway bar setup off from a cordoba onto a 66-70 B body?

I have never tried this, but I have modified sway bars from NON Mopars to fit in both 67-76 A bodies, my own 70 Charger, my 2007 Ram 1500 and a few others. The key is to find a bar with contours similar to what a factory type bar might have been. You can shorten the lever ends, but you cannot do anything about a bar that is too wide or too narrow. You can fab up custom end links to accomodate strange or wierd fitment issues, but that will require welding.
Some like this sort of challenge. I do. I have often spent more time and money trying to make a Volvo part fit a Packard.......( Kidding of course.)
The kits available do make it easy. All the brackets and hardware are included and everything is clean and shiny. When I installed a GM Suburban rear sway bar into my 07 Ram, I had a full days worth of going to the wrecking yard, measuring donor vehicles and pulling one. After that I had to modify the struts/end links and weld brackets to the frame. I spent about $60 total, plus my time. A kit would have taken 2 hours to install but cost almost $250. Your choice.

I'm guessing no, since the rear axle is ~4" wider, and the leaf spring separation was 3" wider.....'70-down, overall axle width (drum face to drum face) was 59.5-61" or so, with 44" between spring centers...'71 up B bodies are 64" wide axles with 47" between spring centers.

When I had my 75 Newport, I put a Cordoba rear bar on it. It was 7/8", and the C body rear bars were 3/4". Bolted on, even the holes in the frame kickup were there. I think they were about 40-41" wide OSM.

I just pulled a rear bar setup off a 75 cordoba in the wrecking yard, a friend of mine is running one on his 72 Gtx and it fits fine. He did say there's differences in the lower mount perch's, they have a large hole in the middle of the plate whereas the earlier b body's have a small alignment hole in the middle.
The pic of the plates sitting on the canopy above show the large holes I'm talking about.
I plan on making it work on my 71