KANSAS CITY, KAN. ? The two new models of Chevrolet’s Malibu that will start rolling off the assembly line here later this year demonstrate General Motors Corp.’s “new focus on the car market,” Gary Cowger, president of GM’s North American operations, said Wednesday.

The world’s largest automaker will have spent six months and more than $500 million getting the plant in the city’s Fairfax Industrial District ready before workers start producing cars for consumers on Aug. 11. Until February, the plant made the Pontiac Grand Prix.

The Fairfax plant will make the new Malibu and the Malibu Maxx. What used to be the Malibu has been renamed the Chevy Classic, and is built in Lansing, Mich.

GM plans to build 265,000 Malibus a year at the Fairfax plant. In 2002, GM sold more than 169,000 Malibus and 130,000 Grand Prixs. GM has not said how much the redesigned Malibu would cost, but executives said Wednesday it would be comparable to the price of the 2003 Malibu.

The Fairfax plant shut down in February and has been undergoing an extensive retooling as it changed to the Epsilon manufacturing system, which allows GM to “build multiple products off of the same architecture,” said Troy Clarke, vice president of manufacturing and labor relations. GM moved production of the Grand Prix from Fairfax to a plant in Canada.

Some workers have helped retool the plant, but most Fairfax employees were laid off during the shut down. Those workers will begin to return to work in June, but a few are not expected back until next April.

Wednesday, the credit ratings agency Standard & Poor’s lowered its outlook to negative from stable on debt issued by GM. S&P credit analyst Scott Sprinzen cited cyclical weakening demand in the North American market, intense pricing pressures, expected weakening of light-truck profitability and market share gains by foreign competitors.