These are stock replacement style sleeves that can be installed with the GM cylinder liner tool. Made out of material that is 200%
stronger than stock and will safely handle up to 600hp with the top cylinders unsupported. These come oversize so they can be machined to your block and pistons. The flange on top will stick up from the deck about .010" and will require decking the block. The bore size is about 85.5mm and will require boring and honing to your pistons after they are installed in the block.