Those cracks at the water passages are common on flat head engines. When I discovered those on my engine, the machine shop didn't miss a beat with lively commentary, "Those cracks are superficial, don't worry about it since you are gonna use sealant on the studs, unless you are dumb... and you don't *look* dumb."
... but the best quote was "If this was a Ford flathead, those types of cracks have a factory part number".
