Im away from home at the moment and this tablet has a mind of its own on the forum but Bill is right to remind people of what I posted some time ago. Many cylinder muffs do not have their bases perpendicular to the bore. From a few I have checked five thou is a typical value. If this is in a fore and aft direction you might get away with it but if it is sideways you will not get away with using the low clearances. Davidd and several others on here know what they are doing with this problem but do not fit lo clearance pistons without getting someone to check for this problem first.