Dart Big M Pro Series Iron Block 31283445 BB Chevy

The Big M Pro block has all of the most requested features of a race series casting without the added weight. With deck heights from 9.600" to 9.800", a +.600" raised cam location, .904 lifter bores, spread oil pan rails and bore sizes up to 4.600", the Big M Pro gives you the ability to build the engine that ideally suits your needs. Features 9.600" and 9.800" deck heights. Raised cam location +.600" clears stroker crank shafts. Oil pan rails are spread .750".Accepts crankshaft strokes up to 5.500"for large displacement applications. Four valley head stud bosses prevent head gasket failures with high compression ratios and/or nitrous oxide. Slotted bosses allow the use of studs instead of difficult to install bolts. True priority main oiling directs oil to the main bearings before the lifters for extra reliability at high rpm. Stepped main oil gallery (9/16" to 1/2" to 7/16") ensures uniform oil supply for all five main bearings. Oil crossover located at the front of the block delivers maximum oil volume to the main bearings and ensures reliable lubrication for the lifters and pushrods on both cylinder banks. Steel 4 bolt main bearing caps are manufactured in-house by Dart to ensure quality and compatibility with the block. Three center caps have splayed outer bolts that anchor the caps to the strongest part of the casting, front and rear caps have vertical bolts for oil pan clearance. Rear main bearing cap uses a standard two piece crankshaft seal without adapters or crank modifications. Uses stock components, with provisions for block mounted oil filter, mechanical fuel pump and stock water pump. Coated cam bearings, freeze plugs and dowel pins are included