Abstract: This invention teaches an improved method and apparatus to make metal alloy castings, such as railroad car connector knuckles. One embodiment of the invention comprises a plurality of core mold assembly units contained within a single molding flask, wherein the mold units are filled with molten metal by way of a common runner and riser system. The said core mold assembly elements may be further comprised of a mold and core assembly formed of the same material, such as phenolic urethane impregnated sand, which is used to accurately replicate the desired shape of a final desired product. This invention eliminates the need to carefully gauge a plurality of part patterns within a single mold flask and reduces the potential for loss of parts, for example by cold shunting, by segregating each part to its own mold isolated mold unit.