BIG M GEN 7 (8.1 LITER) SIAMESE BI

The Dart 31253654 Big M engine block is engineered for strength, reliability, and ease of build, designed for Big Block Chevrolet (BB Chevy) engines. It features a 10.200" or 10.236" deck height, standard 4.600" bore (max 4.625") with siamesed extra thick cylinder walls, and +.300" tall Gen VI style lifters. The block incorporates 4-bolt ductile iron main bearing caps with splayed outer bolts and a true priority main oil system that lubricates main bearings before lifters. A stepped main oil gallery increases oil flow to the crank at high RPM, and a front oil crossover eliminates internal oil leaks around the distributor shaft. It also includes lifter valley head stud bosses and dual oil pan bolt patterns. A parts kit (PN 32000022) is sold separately.