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Reference Information

Engine Block, Cast Iron, 4-Bolt Mains, 4.600 in. Diameter Bore, 2-Piece Rear Main Seal, Chevy, Big Block, Each

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)