You don't even have to grenade anything. Normal tear down show cap walk on the three engines I've seen that had girdles on them. The walk witness marks were no different than when the engine ran without a girdle. That's enough for me to generate an opinion with information available. They don't do anything on a SB except tie the studs together and lighten your wallet.
If you think a girdle is going to help you.. spend the money on a better block. End of story.
