Ditto what California said.
Overheating these engines can often lead to rings contracting into the piston grooves…and sometimes they stick. Fuel inside the cylinder walls will compensate for the compression to quite a high degree…but the crank case oil will show significant signs of diesel fuel contamination when this happens.
Blow by from the down tube (off the valve cover) will tell the story about loss of compression and piston or ring damage and eventually hard starting, oil consumption and fuel in the oil by feeling or smelling the dip stick.
If you go about repairing the engine now, you may get by with a light cylinder wall hone and standard rings (depending on the wall taper). If you wait too long a re-sleeve, valve and seats regrind, and perhaps more will be necessary including the bottom end.
Let us know what you find and in the meantime good luck.
Mark