I just purchased the duff radius arms have my axles etc. I am curious about the width difference from the 79 to 80's radius arm position (were they bolt to the frame). From what I saw on here with the duff arms and brackets It looked like they were just bolting right on? Also what springs should I use I have an 83 F-150 stepside 460 manual trans would like to use 35's, I am also using the 79 spring buckets as well. Sorry if this question has been asked 5 million times before.