Dart Big M Sportsman Big Block Chevy Cast Iron Bare Blocks 31223444

The foundation for a better big block build begins with Dart Big M Sportsman Big Block Chevy cast iron bare blocks. Dart engineered the Big M to be the strongest, most reliable, and easiest to build big blocks on the market.

The Dart Big M Sportsman blocks feature:

* Standard 9.800 in. and tall 10.200 in. deck heights available for Stroker engines
* Standard 4.250 in., 4.500 in., or 4.600 in. bore sizes with 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 Gen VI style lifters. Modifications for Gen IV style are also available
* Scalloped outer water jacket walls improve coolant flow around the cylinder barrels to equalize temperatures
* 4-bolt ductile iron main caps have splayed outer bolts for extra strength
* True priority main oil system lubricates the main bearings before the lifters
* Oil filter pad is drilled and tapped for an external oil pump
* Lifter valley head stud bosses prevent blown head gaskets
* Rear main cap uses standard oil pump and two-piece seal, no adapter required
* Mechanical fuel pump boss, clutch linkage mounts, and side and front motor mounts simplify installation in chassis
* Dual oil pan bolt patterns fit standard and notched oil pans
* Coated cam bearings, freeze plugs and dowels not included
* Small bore 396 version available