the block is bored 84mm and since the rings and pistions are toast you cant put in new pistons. if its one millimeter to big it will blow. I was told Since the heating and cooling of the block,sleeves and pistons do this all at one time since it was built( it molds together) , if try to replace the pistons they wont fit or they well scrap or crack the sleeves. and since i have a sleeve problem i need a new block anyways.