ok first off I'm typeing this on my iPod expect errors maybe.
Now for the post. Can you replace the ball joints on the drag/center link? Or do you have to replace the entire thing? Looking at it they look almost pressed in or something.

 

Are you talking about the front ball joints on your '80? If so, those are real fun to change. lol Anyway yeah I did those on my '81 before. Took me almost 6 hours. Made me appreciate my rack and pinion more on my '82. You replace the ball joint, and tie rod ends together. Not seperate like pre '82.