That you would have to measure out. I already cut mine off to measure for you. They are easy enough to cut off and re-weld in the correct location if they are not.
There are a lot of threads about the swap on here. Most cut the rear and take 3" out, but they fit fine on the dusters at full width. They are the same width as a B-Body rear.
Here are a few links, but there are many more: