DARTON SLEEVES MID SLEEVES HONDA H-SERIES H22A H22A1 H22A4 H23Many production cast iron and aluminum blocks suffer from a design weakness of cylinder stability by nature of poor support at the upper deck area. The manufacturing process of cast in sleeves provides for economy of scale in low horsepower engines, but does not accommodate high horsepower, high boost, or larger bore sizes. Darton has engineered a superior patented (patent #6,799,541) solution by using a unique designed cylinder sleeve which when