gavintwopies is absolutely correct in what he has said about usine the xe pistons and yes they do need to be machined on either face and the little ends made bigger to accomodate the pins to fit the zvh conrods - also needs 4 holes drilled in piston for the oil feed - however gavin does have milling machine and can build you the zvh bottom end as he has done mine - im sure if u flurttered yr eyes a little and asked him he could do it cheap for you - worked for me lol