1965 dart gt spring question

My only concern with spacing the front spring mount is pushing the axle back the inch that I need to get everything in line, maybe I'm wrong but wouldn't that mean I'd have to lengthen the driveshaft and brake lines to match that extra inch?
If you need a full inch, yes. You might start with 1/2” just to see what it gets you, but I understand where you are coming from.