Only because I know you can customize your piston size. Ben said they are 87.5mm, but I dont think with that size of a piston you can go over .040 so I'm thinking that's what it is. You would need a larger piston, like a 90mm for that much of a bore. I have seen .075 bore though when I used the search feature. I know you can customize your compression (these are 8.5:1 ration), but I dont think .075 bore on a 87.5mm would even work. I will check again with the owner.