FYI the later V8s are supposedly better because the equipemnt used to check the metal thickness around the bores was better and they were better cast in the first place.
Conventional wisdom suggest that an engine which overheats more than twice is likley to suffer a cracking of the block under the top deck, about a half inch below the top of the bore which causes the liner to slip in some case because the liners were never driven fully home onto their stops in the bottom of the bore.
So a good service hsitory is important as is a healthy cooling system that appears to have been maintained well throughout it's life.
Look inside for signs of balck death too, a well cared for V8 will be light brown inside, not black.
The gaskets are the later composite type and although they do sometimes fail on their own it's not common, a recent head work suggest deeper problems.
There are hundreds however running about in fine fettle, so choose widely and things will be fine.
