Systems are provided for cooling a cylinder block via bore bridge cooling passages. In one example, a cylinder block with a bore bridge positioned between a first cylinder and a second cylinder, the cylinder block also including a coolant jacket at least partially surrounding the first cylinder and the second cylinder, has at least one cooling passage positioned within the bore bridge. An inlet of the at least one cooling passage has a larger area than an outlet of the at least one cooling passage and at least a portion of the at least one cooling passage has a non-cylindrical geometry formed by a lost core.