Mercedez 352 motor problem

Hello friend ... I look at my problem. I have a minibus with a 352 Mercedezz engine, the truth is I do not understand much of engines but I know it is a good engine, well the issue is that it had a water overheating and something inside is broken, because the mechanic told me, you break a seem or something like that, the matter is that now for what they told me it is perhaps more convenient to buy a used engine than fix that. In that sense I ask you advice to see my possibilities.
I await your answer. Thank you so much.

The engine is good if you can do it, it is better to do it since if they arm it well for you many years and if you buy another you do not know how it comes inside, you also have to have a good rectifier or lathe that works well and because I suppose that the mechanic arises well