High Quality Content by WIKIPEDIA articles! Oklahoma City Assembly was a General Motors automobile factory in Oklahoma City, Oklahoma. Construction on the 4,000,000-square-foot (370,000 m2) plant started in 1974, and it opened in 1979 to produce the X-body cars. The company spent $700,000,000 to convert the plant from building the Chevrolet Malibu car to building the GMT360 SUVs in 2001. The plant was damaged by a tornado on May 8, 2003, but the company repaired the damage and returned the plant to operations just 53 days later.