Products to Compare (max of 3)
Compare These Parts
Talk to the Experts. Call 800.979.0122, 7am-10pm, everyday.
Customer Service
Since 1952
  • Expert Tech Support
  • Huge Inventory
  • Fast Shipping
Talk to the Experts. Call 800.979.0122
Shop By
Street Race Truck More... The Toolbox
Add to Cart
Dart 31131211 Little M Chevy Block, 4.125 Inch Bore
Dart 31131211 Little M Chevy Block, 4.125 Inch Bore

Dart 31131211 Little M Chevy Block, 4.125 Inch Bore

Chevy Small Block V8

0 Reviews | 0 Answered Questions
In Stock
Select your vehicle to verify fitment.
Select Vehicle
Dart 31131211 Little M Chevy Block, 4.125 Inch Bore
Dart 31131211 Little M Chevy Block, 4.125 Inch Bore
Zoomed In Image
Part # 30431211
Add to Cart
Call to Order
Add to Buildlist

Videos & Articles



For those wanting the ultimate cast iron small Chevy block, Darts Little M is your best bet. The Little M features extra thick stock deck heights, stock cam height, stock pan rails, 4 bolt steel main caps, and they are already clearanced for a 3.875" stroke. These blocks have the common 350 main journal diameter with a 4.125" bore size. Two-piece rear main seal.

304-31211 Instructions (PDF)

Must ship truck. Truck Freight Shipping Charges Apply - click here for details

Item Details

Steel Main Caps



  • Extra thick cylinder walls resist cracking and improve ring seal for more power
  • Scalloped outer water jacket walls improve coolant flow around the cylinder barrels to equalize temperatures
  • Priority main oiling system directs oil to the main bearings first for more dependable lubrication
  • Blind tapped head bolt holes prevent water leaks
  • Extra thick decks ensure reliable head gasket seal
  • Standard small block deck height allows use of off the shelf parts
  • Splayed outer bolts on middle main bearing caps prevent cracks
  • Open lifter valley improves return to oil pan
  • Enlarged lifter bosses accommodate offset and oversize lifters
  • 4-bolt billet steel main caps have splayed outer bolts for extra strength
  • Front and rear external oil inlets, crossovers and restrictor provisions to simplify plumbing with external pump
  • Block includes special coated cam bearings, freeze plugs and dowels


Some parts are not legal for use in California or other states with similar laws/regulations

Related Products

More Like This


Q & A

Videos & Articles
  • In this Tech Tip, John discusses LT1 rotating assembly options for a customer looking to build a solid autoX, drag, and occasional strip powerplant for his Firebird.
  • One of the most important parts of your racing operation is the engine. This article gives a detailed overview on how to maintain your engine to get the most out of it for as long as possible. Also learn some tips to prolong the life of your engine.
  • Heath P. tells his story on how the passion for 'hot rodding' was instilled in him by his grandfather. From driving tractors on their family farm to becoming a Ford family, you are in for a good read.

You May Also Like