confessions of problems i have with the dart

Now how does the offset spring kit work, does it require welding or just a bolt on? If I could get a 275 60 15 in there with just the offset spring kit, that would be great!
Just spring perches moved in and re welded to housing 1/2" or 3/4" depending on kit.
By the way, that car sounds awesome,and familiar....LOL