GM previously announced that the all-new 1997 Park Avenue would be built at the Orion plant, while production of the current Pontiac Bonneville would move from Orion to the Buick City plant in Flint, Mich., for the 1996 model year.
The company found that while there was enough unused floor space at Orion to build the Park Avenue, the space wasn't in the right part of the plant, said Don Hackworth, vice president of the Midsize and Luxury Car Group.
Construction of the 185,000-square-foot addition to the 3.7-million-square-foot plant is scheduled to begin in January.
The expansion is not expected to affect employment, currently 4,500 workers.
The addition will house a new, flexible body shop.
Besides the Bonneville, the Orion plant currently builds the Oldsmobile Aurora, Ninety Eight and Eighty Eight, and Buick Riviera. The Ninety Eight will be discontinued after 1996.
Besides the Park Avenue, Buick City currently builds the Oldsmobile Eighty Eight and Buick LeSabre. The addition of the Bonneville will make it an all H-body plant.
The '97 Park Avenue goes to Orion because it is based on the G-car platform that now yields the Aurora and Riviera.