Tonawanda Engine is a General Motors engine factory in Buffalo, New York. The plant consists of three facilities totaling 3.1 million square feet (290,000 m2) and sits upon 190 acres (77 ha). The factory receives cast engine blocks from Defiance Foundry in Defiance, Ohio and Saginaw Metal Casting Operations in Saginaw, Michigan, and received engine block castings and cylinder heads from the former Massena Castings Plant in Massena, New York.