Indy's Maxx block is fully water jacketed, and designed for both street and race applications. The cylinder walls are centrifugal-cast sleeves, which are a dry-sleeve configuration in the block. This provides the best in bore stability, rigidity of the decks, and reliability in long-term operation. Notice also the beefy ribbed lifter valley and high-strength Indy-sourced head studs. Get the idea that the guys at Indy aren't fooling around? The engineering is first-rate.