i found a bad scratch down both sides of one of the cylinders.theres a mark on the sides of the pistons and the rings look like new but i cant figure out what caused this?the scratch is about 2mm deep and since my blocks 40thou already now i need a new block fantastic

anyway what i want to know is there any diference with 250 blocks from cortys to falcons or are they all the same.and does anyone have one theyed like off there hands