I have seen 3 LS blocks at the Speed shop getting sleeves in the last 4 months. All of them had a crack into the deck and wasn't able to build. All cracked around the same spot, and all heavy hitter engines. All of them were on nos and in the low 4's.At any given time there is 30 or more engines in the shop being built. 90% of them are gm. They always run the best, just before they blow up.