Dart engineered the Big M to be the strongest, most reliable, and easiest to build big-block on the market. With available deck heights of 9.800" and 10.200" and bore sizes of 4.250", 4.500" and 4.600", the Big M gives you the versatility to build a wide variety of engine combinations. Dart redesigned the lubrication system to create a true priority main system that oils all of the main bearings before the lifters for extra reliability. Their 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 their oil crossover eliminates internal oil leaks around the distributor shaft. The result: more oil at the bearings and pushrods where it's needed, and less power-robbing crankcase windage. Dart added two slotted head stud bosses on both sides of the lifter valley so you can use studs instead of hard-to-install bolts to take the place of the "missing" head bolts. The Big M is fitted with billet steel 4-bolt main caps for ultimate bottom end strength. Dart machines Big M blocks in-house on precision CNC equipment to ensure quality and to eliminate the need for expensive blueprinting.
Sportsman blocks have nodular iron 4-bolt main caps. Cam bearings, freeze plugs and dowels are not included.
