DART DA31213344 Chev Big Block Big M Iron Engine Block 4.250 In. Bore

Features:

• 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
   

Specifications:

• Material: Superior Iron Alloy
• Bore: 4.250''
• Bore & Stroke: 4.625'' x 4.750'' max recommended
• Cam Bearing Bore ID: 2.1195'' - 2.1205''
• Cam Bearings: Special coated, grooved, with 3 oil holes
• Cam Bearing OS: +.010'', +.020'', +.030''
• Cam Bearing Press: .002''
• Camshaft Position: Standard
• Cam Drive: Standard Timing chain, gear drive or belt drive
• Cam Plug: Standard BBC 2-7/32'' (2.218'' dia)
• Cubic Inch: 632'' max recommended
• Cylinder Wall Thickness: .300'' min @ 4.625'' bore
• Deck Height: 9.800''
• Deck Thickness: Adequate for all applications
• Fuel Pump: Mechanical pump provision
• Fuel Pump Pushrod: Standard BBC
• Freeze Plugs: Press in cup plugs
• Head Gasket: Fel-Pro 375-1037, 1047, or 1067
• Inner Head Stud: 2 slotted bosses per side
• Lifter Bores: BBC .8427'' - .8437''
• Lifter Galley: Raised .350'' for longer lifter bore
• Lifter Type: Roller - Gen VI (+.300'' longer), Solid - Mark IV
• Main Bearing Size: Standard BBC
• Main Bearing Bore: 2.937'' - 2.937''
• Main Caps: 4-bolt steel billet
• Main Cap Register: Deep stepped register on each side (No need for dowels)
• Main Cap Press: .005''
• Main Cap Bolts: All 1/2'', #2, #3, #4 have splayed outer bolts
• Oil System: Wet or Dry Sump - Main Priority Oiling
• Oil Galley, Main: Stepped, 9/16'' - 1/2'' - 7/16''
• Oil Galley, Filter-Main: 5/8''
• Oil Filter: Stock Oil Filter Location
• Oil Pan: Standard pan bolt pattern, extra bolt holes provided for strokers
• Rear Main Seal: Standard 2-piece seal, Fel-Pro 375-2918
• Rear Main Thrust Width: 1.622'' - 1.624''
• Serial Number: On main caps
• Starter: Mounts in standard location
• Stud Hole, Head: Blind holes
• Timing Chain/Gears: Standard
• Timing Cover: Stock Cover
• Torque Specs: All 1/2'' bolts - 105 lbs
• Weight: 4.250'' bore - 260 lbs

• Quantity: Sold individually
• Rear Main Seal Style: 2-piece
• Engine Block Material: Cast iron
• Main Journal Type: OEM
• Cam Bearings Included: Yes
• Engine Block Style: Stock/OEM standard Deck
• Engine Block Style: Stock/OEM standard deck
• Finished Cylinder Bores: No
• Freeze Plugs Included: Yes
• Main Bearings Included: No
• Main Cap Fasteners Included: Yes
• Main Cap Material: Steel
• Main Caps Included: Yes
• Raised Cam Location: No
• Main Bolt Style: 4-bolt
• Engine Block Weight (lbs.): 280
• Cylinder Bore as Shipped: 4.24 in (107.696 mm)
• Cylinder Bore Diameter: 4.25 in (107.95 mm)
• Deck Height: 9.8 in (248.92 mm)
• Manufacturer's Part Number:: 31263344