2008 F350 rear spring graft onto 2005 F350

I am trying to find someone whom may know if 2008 F350 rear springs will work with the 2005 F350 spring perches and mounts, if I simply move the front mounts forward by about 10 inches or so.  The 2008 F350 has much better ride quality over free way washboards and the claim is because the rear springs are 10 inches longer in front of the axle.  So I want to know if move the front spring mounts forward, with the springs fit in both mounting brackets as well as the axle perches. Also will the axle be positioned in the same place (i.e. is the length of the 2008 rear spring the same from the axle to the rear spring mount), and will the ride height be the same? I would like to know this before I purchase the springs and find out otherwise. Thanks!