plain and simple, he is looking for best of the bunch he has. that would be the block with the thickest cylinder walls hands down. more structure promotes better ring sealing and minimizes out of round condition under any duress. what can be more simple than that? the only way to check is sonic testing with qualified equipment and some one who knows how to use it.
just because you built a engine way back when, bored and honed and checked nothing and it ran well for you doesn't mean it ran as good as one could of if you took the time and spent the money to find a block that was the best of what was truly available.