new 8 3/4 length?

Hi. I got a E body rear in my 73 Duster. It's not narrowed, but
the spring mounts have been moved in to the A body springs.
I run 255/60-15 on the back with 15x8 rims. The back spacing is
4 1/2 inch. If I changed to a 5 in. back space I could possibly
even run a bigger tire. So if you don't want to go the extra cost
of narrowing it. Mock it up an see how it would work for you.
There is a pic in my garage with this setup. See what you think.