865 pistons were discontinued few years ago... I managed to get brand new set few years ago but what I read they are not what wiseco claimed at the time saying that checking compression on my two bikes reading was; america 904 wiseco both cylinders 150, bonnie with 865 wiseco so call hi comp pistons 165 170.....cheapest way to upgrade is to buy 865 cylinders and pistons from ebay and do what I call cheapo ghetto big bore (my bonnie has it plus better pistons I got but otherwise would get stock pistons) keeping 790 cams ...TP usa piston kit cost 994$ with cams did ask in the past about pistons only but they never been back to me, and you really need low milage 865 cylinders for that kit......from my expirience they 813 cams are not much better from 790 cams....they probably works better on higher reves
