You'll have more tied up in that 1600 than it's worth before you know it. A good complete runner is only worth about $2500. Why not take apart the hydra power you have first to find out what's wrong before spending $600. It won't cost you anything and you need to pull it anyways.
And if you don't need a top link right away, just keep tabs on ebay. Except for the U, you can buy the rest brand new and complete for $180. Call rock valley tractor parts and see what they get for one. You can dicker with those guys...and use the fact that new parts are $180 to negotiate a better price for used.