Help-K member swap 1975 Dart Sport
K frame differences except 67 which has an odd idler arm
Must be six if you have a slant or V8 if you have a V8 otherwise welding/ fab required
Engine mounts went to "spool type" in 73. Also in 73, the anti-sway bar is different and later type goes through middle of K member, earlier mounts UNDER. So all you need is appropriate year range of mounts/ engine brackets to match.
You can change all other pieces.
Steering link: FOUR parts must match. Center link, idler arm, pitman arm and steering box (spline) must all be same either 72/ earlier or 73/ later. Outer rod ends can be either year range Any year steering box mounts to K, only difference is whether you want power/ manual box and the pitman spline size
Lower arms can be any year 67/ later depending on if or not you need sway bar tabs
Upper arms depends on drum brake vs 73/ later disk brake Ditto spindles