Rebuild it, usually the best option, at least you knows it been done properly (especially if you do it yourself)
I have seen so called recon engines with odd size bores :schocked:, timing out and even rattley bearing!!
a Hotchkiss engine we recently used has suffered low oil pressure since fitting, it was supposadley brand new! next on the list to fix!!!
i rebuilt my own jeep engine 6 years ago and have covered 12,000 trouble free miles since :-D, i even run it on straight unleaded and have not suffered any valve issues :-)
Be careful of Ford blocks, i had one apart a while ago that had been completely rebuilt, had even welded all the external cracks, unfortunately they did not spot the internal crack, it lasted a couple of miles!!!!
Baz