Finally investigated why my Fiance's old 2001 WJ 4.0 quit last winter. Turns out it looks like it has the dreaded early "0331" cracked head at about 180K miles. I've found a 2002 4.0 from a TJ Wrangler. Fella is converting to diesel for his crawler and doesn't need the stock engine anymore. Do Wrangler and GC use the same 4.0 engine block in '01 & '02? So I could swap the 2002 Wrangler 4.0 into the 2001 GC directly? The '02 engine would get me the updated head, so the crack won't happen again.

Then my other choice. For about the same money ($700), I could buy a used '02-04 head + a light rebuild on the stock '01 short block. Lots of labor for me, but I'd know what I have when I'm done. If the short block is hurt (beyond bearings), this bet would be off because the cost would escalate.
Or, just swap in the complete Wrangler engine (100k miles) for the same $700 and hope for the best, quicker and less labor intensive. Either engine would get a new oil pump, front and rear seals and core plugs while the engine is out. Your thoughts?

the engine should be a direct swap. 2000+ TJ and WJ used the same engine AFAIK

The XJ/early TJ block has different engine mount points if I remember correctly

Thanks Dave. I would have bet a small amount of money the WJ and TJ blocks were the same, but not $700. It was in the back of my mind that Wrangler 4.0s did have different engine mount bosses at some time in the earlier years.

it's the same, but make sure you get a good set of pics, or hand drawn diagrams, showing every switch, sensor and connector. there could be slight differences in these pieces, year to year.

distributorless vs distributor come into play? I know the g.c. got them before the others.

I would drop it in as-is and not even crack it open. watch out for the sensors, sometimes connectors change year to year.

I'm really torn on this. Not sure I even should put $700 in her old WJ and run it myself, or part it out & save its good parts for the WJ she's driving now. Money's tight now, hard do justify putting money into this when I don't really need another vehicle. Just that the WJ would be a little easier on gas as a work truck than the full size Ram 4x4 I'm running now. A few MPG better than the truck, but not a lot. Insurance on another vehicle? Uggg. Another vehicle to care for? Uggg.