[rotorwrench]

If a guy wants a bigger bore, you have to take them out. If a guy want's longevity and doesn't care about having a standard bore, you replaced the sleeves & pistons. All the little 9N, 2N, & 8N plus the 600, 800, & 900 series tractors used sleeves. I think that's why you still see so many of them still working out there. You can still get pistons & sleeves easily but engine blocks, not so much.