Revolution aerospace-grade all-aluminum cylinders with nickel-silicon-carbide electroplated bores, which means NO SLEEVING; allows larger bore sizes and less friction for more horsepower, lower temps, and a longer lifespan Also includes Wiseco forged pistons with rings (that are specifically designed for optimal compatibility with Revolution Performance's cylinders), wrist pins, circlips and high-performance head and base gaskets Replacement head and base gasket sets available separately Includes 10.5:1 Flat Top Piston Includes 3.875" Bore cylinders Silver cylinders; Case boring required for all Revolution Performance Monster Big Bore Kits; ; NOTE: For replacement pistons and rings, see Revolution Performance Big Bore Piston Kits.