Well how or what are you plaining to use's. 1973- 1980 frames are different from the 1981-1987 but can fit nice but some mods have to be done depending on what your useing or wanting to use. A little more info try to tell you more on the 4x2 set ups the Front bumper differ so you will need to know what yr style your going to use. 83 needs the 81- 87 body mounts rad mounts on the 79 frame. Are keeping the frame ( 79 ) brakes SAE or useing the ( 83 ) cab master brakes Metric, Now you can cut lines at the master from the frame & put metric ends on to conect to the metric master. Or vise a versa . 1980 was the yr metric started 1980 could be both SAE or Metric power steering pump fitting, Gear box, brakes fitting, Flex hoses. Other then that they can bolt up ok, you got two conplete truck's to work with. Well this help you a little I hope. Oh bye the way I have a 1977 Frame with a 84 front clip little a lot more work.
