Your engines already have a top end girdle. They are known as your intake and heads. If you haven't already read......stock block failures originate in the mains which then the cracking moves upward. Snake oil is all that is. Your money is better spent elsewhere like in machining. Get the block stress relieved, torque plated and align honed with all bolts in place. Don't skimp on balancing the rotating assembly, either.
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Helmut