Like Jerry said, stitching, or as Gandpa called, cold welding, is a viable way to save a block. Back when my uncles races quarter midgets, Grandpa repaired a cracked Continental 2 cylinder engine that way. My Uncle John raced that car successfully after that, even beating out twin engine karts with it.
Something that does bother me, though, is that he "found" the "crack" after hot tanking and machining the block. Has he shown the crack to you? I'm not trying to say that he's dihonest, but the mention of it being a truck block and finding a problem after doing the work raises red flags to me. Is it a 4 bolt main block? Around here, the dirt track racers will pay top dollar for a 4 bolt main block, and I have heard of a few shops that will sell someones engine off to a racer for the easy money, then say that the block was "bad". That actually happened to a neighbor of mine. They ended up having to give him a new 4 bolt block to replace the one they sold.
