Edelbrock engine blocks are the ideal starting point for any high-performance build that demands the quality and precision of an American-manufactured product. The Edelbrock Big-Block Chevy Block #4500009 is an unfinished bare cast-iron engine block with a rough bore size of 4.495-inches (+/- .001), a rough deck hei ght of 9.813 inches (+/- .005), and a cam bearing bore ID of 2.120 inches with a two-piece rear main seal. The unfinished deck and bores allow an engine builder to machine the block to nominal deck heights and bore diameters using their own finish specifications. This BBC #4500009 Block features Siamese cylinder bores and splayed four-bolt mains to meet the demands of a high-horsepower build. Features include a standard BBC head bolt pattern and camshaft position, standard BBC main bearing size, standard BBC starter location, and compatibility with standard BBC (Gen IV, V and VI) timing chain, gears and Mark IV 10-bolt timing cover.