Description:

NOTE: DART'S FOUNDRY HAS FILED BANKRUPTCY MAKING FUTURE SUPPLY UNCERTAIN. WE HAVE ONE 10.200" DECK, 4.560 BORE BIG M IN STOCK. IT IS ONLY AVAILABLE FOR PURCHASE FROM US AS PART OF A BUILD. SORRY FOR THE INCONVENIENCE

Overview
If you want a BBC block that can handle big horsepower, the Dart Big M block is for you!  With multiple deck heights and bore sizes up to 4.600", the Big M block gives you the versatility to build a wide variety of engine combinations for street, race or marine. Dart's maximum recommended bore and stroke allows displacements up to a massive 638 cubic inches (4.6125" x 4.75"). A true priority main oiling system oils the main bearings before the lifters for extra reliability.

Features

-  Standard 9.800", 10.200" and 10.400" deck heights available for stroker engines.
-  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).

-  0.400” raised cam versions available

-  Use +.300” tall Gen VI style lifters

-  Scalloped outer water jacket walls improve coolant flow around the cylinder barrels to equalize temperatures.
-  4 bolt main steel caps have splayed outer bolts for extra strength. (Big M Sportsman = ductile iron caps)
-  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.
-  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 any chassis.
-  Dual oil pan bolt patterns fit standard and notched oil pans.
-  Small bore 396 version available
-  Parts kit included for Big M; cam bearings sold separately

These blocks are available in any level of finish from ready for "as-produced" to fully machined to a complete custom crate engine.  Whatever your needs, we can help.

Optional fully prepped block ready for assembly includes:
-Square deck to height and CNC chamfer cylinders on our 4-Axis Rottler CNC
-Deburr entire block & main caps
-Diamond CNC hone
-Align-hone mains, hone lifter bores
-Final clean block and paint with primer in your choice of colors
-Install cam bearings & test fit cam
-Install oil galley and freeze plugs

Your block would be machined on our state-of-the-art Rottler CNC 4-axis and CNC diamond hone for unparalled precision. This in turn yields superior performance and longevity as decribed in the video below.

Please call us at 815-725-2727 for questions and pricing on finish machining, short blocks, long blocks or full crate engines.

Buy your parts from people who use them!