A method of simultaneously manufacturing a plurality of crankshafts includes positioning a core system having a plurality of individual cores within a cavity of a mold having first and second halves forming an exterior shape of the crankshafts. The crankshafts' exterior shape includes a plurality of pin bearing journals and a plurality of main bearing journals. Each of the cores passes through each of the crankshafts. At least one core passes through at least one of the pin bearing journals and at least one other core passes through at least one of the main bearing journals. The method also includes introducing into the cavity molten metal to form the crankshafts. As the metal flows into the cavity and around the plurality of cores, a hollow section extending through at least one of the pin bearing journals and at least one of the main bearing journals of each crankshaft is formed.