Oiling System Tech Tip

Dart 31223344 Big Block Chevy Big M Sportsman Cast Iron Engine Block Features:

• Ductile iron 4-bolt mains caps for ultimate bottom-end strength
• Siamesed extra thick cylinder walls to resist cracking and improve ring seal
• 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

Dart 31223344 Big Block Chevy Big M Sportsman Cast Iron Engine Block Specs:

• Material: 220 BHN cast iron
• Main Journal Type: 454 Main
• Deck Height: 9.800 in.
• Cylinder Bore as Shipped: 4.240 in.
• Cylinder Bore Diameter: 4.250 in.
• Finished Cylinder Bores: No
• Main Caps Included: Yes
• Main Cap Material: Ductile Iron
• Main Bolt Style: 4-Bolt
• Main Cap Fasteners Included: Yes
• Lifter Bore Diameter: .842 in.
• Camshaft Bore: Standard
• Provisions for OE Roller Lifters: No
• Main Bearings Included: No
• Rear Main Seal Style: 2-Piece
• Oil Pan Rail Type: Dual pattern
• Raised Cam: No
• Cam Bearings Included: No
• Freeze Plugs Included: No
• Weight: 280 lbs.
• Requires Dart Cam Bearing, Freeze Plug Parts Kit 32000002 or equivalent (sold separately)

Emissions Note:

This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.

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