Dart Big M Bbc Chev Comp Iron Block 9.8 Deck 4.50 Bore 31263444

Dart engineered the Big M block to be the strongest, most reliable and easiest to build big block on the market. With multiple deck heights and bore sizes up to 4.600", the Big M Sportsman block gives you the versatility to build a wide variety of engine combinations. A true priority main oiling system oils the main bearings before the lifters for extra reliability.

Features:

• Standard 9.800" and tall 10.200" deck heights available for stroker engines.
• Standard 4.250" , 4.500" 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.
• Scalloped outer water jacket walls improve coolant flow around the cylinder barrels to equalize temperatures.
• 4 bolt billet steel main caps have splayed outer bolts for extra strength.
• Crankshaft tunnel has clearance for a 4.500" stroke crank with steel rods without grinding.
• 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.