what size?

something to be clear about is usually the bore size will be increased .010 inches at a time, which equates to about .25mm. so you need to be sure of what measurement they are using
 
I had is measured the other day and it is .37 over which equates to a .40 over piston. But I had an airleak and it got f*#ked up. Im probably going with a .50 over this time .60 at the most.
 
just figured i'd make sure that was clear............because if i got an email saying you needed a .50 over piston i would send a 66.50 piston not a 67.25..............gotta make sure you specify
 
just wanted to save you some serious frustration man......nothing would suck more than emailing a company saying "i need a .50 over piston" and they send you a 66.5mm