No straight answer to that one I'm afraid.
Depends upon the state of the rest of your vehicle - it might be more effective to walk away.
If lets say there was more to this than an emotional attachment and it was an economic decision then you have 2 options (well 3 or 4 or 5 or 6 or 7!! and some permuations on top of that) - As well as cost, the time you can afford to have vehicle off the road is a factor.
1. Rebuild yourself - needs knowledge, skills, tools and facilities.
2. Swap out with an exchange recon short engine and keep original head.
3. Swap out with an exchange recon full engine.
4. Option 2 with new rather than recon.
5. Option 3 with new rather than recon
6. Subcontract 2-5 for swap out.
7. DIY 2-5 swap out.
You can research the cost of the options yourself there may be recommendations for a stateside source of remanufactured engines of pedigree - I cannot offer as based other side of the pond.
You could get by with remarkably little in way of tooling and you could hire engine hoist and engine stand (you can do without latter but makes life much easier and probably facilitates quality work). Otherwise normal tooling + torque wrench. Once dismantled you could take to friendly machine shop for dimensional inspection and any work required on block/crankshaft).
More experienced and stateside experts (Larry?) please chip in here.
230 TE (W124) 1989 with 153,000 miles on the clock - hoping for at least another 100K