Abstract: A manufacturing process for reverse building complex-shaped vehicle fuel tanks using complementary female mold half sections which, when joined together about their mating peripheral edges, exactly duplicate the fuel cavity framework of the vehicle into which the completed tanks are to be mounted. Whereas previous reverse building processes employed light weight, air-curable, non-tear fabric such as nylon fabric reinforcement to both halves of the female molds, such fabric is applied only to the mold for the top half of the fuel tank of the present invention. Self-sealing, autoclave curable materials are used in the bottom half of the fuel tank, thereby providing improved ballistic protection to the lower portion of the tank.