Dart Big M Sportsman Engine Block Big Block Chevy 4.500" Bore, 10.2" Deck Height

Dart Big M Sportsman Engine Block Big Block Chevy 4.500" Bore, 10.2" Deck Height

Regular price
$4,115.00
Sale price
$4,115.00
Regular price
$4,427.50
Sold out
Unit price
per 
Tax included. Shipping calculated at checkout.

 

Dart Big M Sportsman Engine Block Big Block Chevy 4.500" Bore, 10.2" Deck Height
  • Part # 31223454
  • Material: Superior Iron Alloy
  • Bore: 4.500"
  • Bore & stroke: 4.625" x 4.750" (max recommended)
  • Cam bearing bore ID: 2.120" Std.
  • Cam bearings: Coated, grooved, w/3 oil holes PN# 32210030
  • Cam bearing O.S. +.010", +.020", +.030" available *Call for Part numbers
  • Cam bearing press: .002" Camshaft position: Standard or +.400” (Option / Big M²)
  • Cam Drive: Timing chain, Gear drive & Belt drive
  • Cam Plug: Standard BBC 2.215" P/N: 32520000
  • Cubic Inch: 632" (Max Recommended)
  • Cylinder Wall Thickness: .300" min @ 4.625" bore
  • Deck Height: 10.200"
  • Deck Thickness: Adequate for all applications
  • Dist. Tap Hole Valley: None
  • Fuel Pump Boss: Mechanical pump provision
  • Fuel Pump Pushrod: Std. BBC 
  • Freeze Plugs: Std. Press in cup plugs 1 5/8 “dia.
  • Head Bolt Pattern: Std. BBC Big M Bolt Pattern
  • Inside Head Studs: P/N: 64210240 (Not included)
  • Lifter Bores: BBC .8427" - .8437" + .300 Taller Gen V, VI style
  • Main bearing size: Std. BBC
  • Main bearing bore: 2.937" – 2.938"
  • Main caps: Ductile Iron (Sportsman) 4 bolt
  • Oil system: Wet or Dry Sump - Main Priority Oiling
  • Oil Galley, main: Stepped, 9/16" – 1/2" – 7/16"
  • Oil Cooler Holes: None (Can use aftermarket inline)
  • Oil Galley, filter main: 5/8"
  • Oil Filter: Stock oil filter location
  • Oil Pan: Std. BBC bolt pattern & Stroker pattern at mains
  • Rear Main Seal: STD 2 pc seal / Felpro# 2918
  • Hyd. Roller Provisions: None
  • Serial No. On main caps / Front passenger side below deck
  • Starter: Mounts in standard location
  • Stud & bolt holes: Blind tapped
  • Tapped Holes: Std. English Thread & Pitch
  • Timing chain / gears: Std. BBC
  • Timing Cover: Gen IV / V stock 10 bolt cover or Dart +.400” Aluminium cover P/N: 67240002 (Includes Gasket)
  • Torque Specs: All ½" bolts – 100 ft lbs w/CMD #3 high pressure lube
  • Weight:  4.500" bore (260lbs) 

 

 

About the Dart Big M

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 Big M is fitted with Billet Steel 4-bolt main caps for ultimate bottom end strength. The Sportsman block is fitted with Ductile Iron 4-bolt main caps.

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. Modification for Gen IV style available.
• 4-bolt main bearing caps in Ductile Iron have splayed outer bolts for extra strength.
• True priority main oil system lubricates the main bearings before the lifters. Our stepped main oil gallery (9/16“ to 1/2“ to 7/16“) increases the flow of oil to the crank at high RPM, and our 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. 32000002