Dart Big M Mark IV Big Block Chevy Full Water Cast Iron Bare Blocks

Dart is committed to producing the best engine components available, including the Dart Big M Mark IV big block Chevy full water cast iron bare blocks--engineered for applications where water between the bores is a requirement. Siamese bore versions are also available for larger bore applications. Features of the Dart Big M Mark IV big blocks include: * Standard 9.800 in. and tall 10.200 in. deck heights available * Standard 4.250 in. or 4.600 in. bore sizes * MRK IV blocks use the 2-piece rear seal design, while Gen V and Gen VI blocks use a 1-piece seal and a different timing cover pattern * 4-bolt main bearing caps in ductile iron have splayed outer bolts for extra strength * True priority main oiling (lubricates the main bearings before the lifters) * Mechanical fuel pump boss, clutch linkage mounts, and side and front motor mounts simplify installation in chassis * Lifter valley bosses for OE style roller lifters and retainer; (Non-Siamese blocks only) Show Less