Dart 31274454 Short Blocks

Big M Aluminum Chevy Big Block
Ductile Iron Main Caps

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.
• 2 bolt front and rear and 4 bolt interior ductile iron main caps have splayed outer bolts for extra strength OR 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.
• Available in traditional Gen IV style, or in Gen V or Gen VI style with one piece rear seal.
• 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.
• Coated cam bearings, freeze plugs and dowels are included.