It's common, actually a forgone conclusion that the stock sleeves will let go on a stock setup once a certain HP is reached. They actually blow out or break out because of cylinder pressure. This is highest when the piston is at the top of the cylinder and it fires trying to push down on the piston. More HP means more force pushing down on the piston. But it also means pressure pushing outward on the cylinder wall. This only happens to a large degree at the top of the cylinder wall. When the piston is at the top of the cylinder or close to it, no force can push outward into the sleeves because those are in the crank case area which has nearly zero pressure. As the piston moves down more sleeve is exposed but pressure is also reduced. So much so that when the piston is down even half an inch, pressure is no longer an issue at all.

To address this problem some have replaced the sleeves. This wouldn't be all bad if you were only addressing the problem. However, as I pointed out in my other thread, the Darton sleeves change everything and hog out your block. THey add 12 pounds to the build. In reality you only need the very top of the sleeve to be strong.

We do just that and more with the girdle. Discussing how strong it is, is really mute because it is no longer the weakest part of the engine. The head gasket failed around 1000 engine HP on our test motor. In a normal build w/ upgraded sleeves, the head gasket would at a lower HP levels as less of the gasket is supported.

 

So in conclusion, if I want to bore to 88mm, what is the best solution?
Thank you
Christian