make sure you find someone with a great reputation for welding cast Iron , to do it correctly it needs to be heated in an oven to a certain temperature and held at that temperature until entire block has reached temperature evenly ,,has to be welded at that temp and heat kept on even keel until repairs are completed , then then cooled in increments over a period of time. saw it done a few times when I was young evidently my memory is as good on exact details as it use to be. Don't just look for car guys for this type of repairs , if possible look to find European or Russian immigrant professional welders as cast iron is a cheaply produced metal widely used in the east and they experts in cast iron repairs. Indy Cylinder head use to do it years ago.