dana 80 for drw is wider than single rears and the full floating shafts /hub set up is a lot longer than any single wheel full floater.basically the inside rear wheel sits in roughly the srw stock position,the inside wheel is reversed though so the mounting surface is all the way to the outside of the tire.the front wheels are supposed to center the rears .hence the 6" adapters and the outside rear startes at the adge of the bed and goes out from there.if you switch to the drw 80 on a srw truck you are going to have a much wider track in the back and the hub is going to protrude beyond your stock wheels.you could space the front to match and use heavy backset wheels which would likely look kool and handle well also.
.(btw all superduty drw front axles from 99 up to at least 07 have the 170mm bolt pattern ).so all dually adapters will bolt on but the 05 and up have 200mm outer bolt pattern