I will give you the exact measurement tomorrow, but if the crack is at the very top you can sleeve it. The top 1/2-3/4" section of the Darton sleeve requires cutting out the complete original sleeve. If the crack is at the top and only goes down a little bit it will be cut out anyway. You just have to make sure the crack doesn't keep going the way down. Also if the crack is only in the inner liner and doesnt reach the outside of the OEM sleeve you can also still sleeve it since it will be machined away.