Hi,

I have an 87300tdt that developed a nasty, unrepairable head problem that was going to cost thousands to repair properly. On top of that, the car had 171,000 miles on it, so other items on the engine were likely to need repair soon. Calling around to a few salvage yards yielded a complete engine with starter, injection pump, alternator, flywheel for $1100.00. Considering that most reputable yards will give you a "if it doesn't work, bring it back "
warranty, it seemed like a good deal. It seems as if you are pretty handy with repairs, so an engine swap shouldn't be too hard, especially if you have help. As it turns out, my "new " engine has been running fine for four years with no oil consumption between changes, and I got a bunch of spare parts as backup. Of course there is the risk of getting a bad engine, or one that needs some repairs but if you do the labor, all you risk is time. If you are concerned about keeping your car original though, spend the big money and have your engine overhauled.
If the only problems your engine has is leaks, consider having it re-sealed by a good shop. It will cost you some money, but a lot less than a complete overhaul.