Dart engineered the Big M to be the strongest, most reliable, and easiest to build big block on the market.
With deck heights of 9.800” and 10.200” and bore sizes up to 4.600”, the Big M gives you the versatility to build a wide variety of engine combinations.
The Sportsman block is fitted with Ductile Iron 4-bolt main caps. The Big M is fitted with Billet Steel 4-bolt main caps for ultimate bottom end strength.
Features
- Standard 9.800” and tall 10.200” deck heights.
- Standard 4.250”, 4.500”, 4.560” or 4.600” bore sizes with siamesed
- Extra thick cylinder walls to resist cracking and improve ring seal (minimum .300” thick with 4.625” bore).
- Uses +.300” tall Gen VI style lifters
- 4-bolt main bearing caps in steel or Ductile Iron have splayed outer bolts for extra strength.
- True priority main oil system lubricates the main bearings before the lifters.
- Dart stepped main oil gallery (9/16“ to 1/2“ to 7/16“) increases the flow of oil to the crank at high RPM,
- Dart 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.
- Big M Sportsman: Parts kit sold separately (PN 32000002).
- Engine Block Material:
- Cast iron
- Engine Block Style:
- Aftermarket/OEM standard deck
- Deck Height:
- 9.800 in.
- Cylinder Bore Diameter:
- 4.500 in.
- Maximum Bore Diameter:
- 4.625 in.
- Cylinder Bore as Shipped:
- 4.490 in.
- Finished Cylinder Bores:
- No
- Maximum Stroke:
- 4.750 in.
- Main Caps Included:
- Yes
- Main Cap Material:
- Ductile iron
- Main Bolt Style:
- 4-bolt
- Main Journal Type:
- 454 mains
- Rear Main Seal Style:
- 2-piece
- Main Cap Fasteners Included:
- Yes
- Main Bearings Included:
- No
- Engine Block Weight (lbs.):
- 260 lbs.
- Raised Cam Location:
- No
- Cam Bearings Included:
- No
- Freeze Plugs Included:
- No
- Finish:
- Natural
- Quantity:
- Sold individually.
- Notes:
- Block bores are .10 undersized to allow for piston set up.
- Make:
- Chevrolet
- Engine Family:
- Chevy big block Mark IV
