Iron Blocks W/Billet Steel Main Caps
- Ductile iron 4-bolt mains caps for ultimate bottom-end strength
- Siamesed extra thick cylinder walls to resist cracking and improve ring seal (minimum .300 in. thick with 4.625 in. bore)
- Uses +.300 in. tall GM Gen VI style lifters
- Crankshaft tunnel has clearance for a 4.500 in. stroke with steel rods without grinding
- Main bearing caps have splayed outer bolts for extra strength
- True priority main oil system lubricates the main bearings before the lifters
- Stepped main oil gallery (9/16 in. to 1/2 in. to 7/16 in.) increases the flow of oil to the crankshaft at high RPM, and front oil crossover eliminates internal oil leaks around the distributor shaft
- Lifter valley head stud bosses prevent blown head gaskets
- Dual oil pan bolt patterns fit standard and notched oil pans
- 220 BHN cast iron block material
- .842 in. lifter bores
- Press-fit freeze plugs
- 2-Piece rear main seal
- Includes block parts kit 301-32000002 - coated cam bearings, freeze plugs and dowel pins
The Strongest and Most Reliable Big Block Available!
Dart has reinvented the "Rat Motor" with their cast-iron Big M big blocks. Working with top builders and Dart's own championship-winning Pro Stock engine department, they have designed a no-compromise, user-friendly block that solves the problems that have plagued big-block racers for years. Each unit is in-house machined on precision CNC equipment to ensure the highest quality and to eliminate the need for expensive blueprinting.
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