DETROIT -- Product chief Robert Lutz thinks General Motors can sell more than 100,000 units of the Chevrolet Camaro -- and says that's the number required for GM to build a production version of the concept unveiled at the Detroit auto show.

GM is doing "intense work" on engineering for a production version and analyzing the business case, Lutz, GM's vice chairman and global vice president of product development, said in an interview with Automotive News.

He added: "Is it an approved program? No."

In January, Lutz said he expected a decision on building the sporty coupe within six months. GM executives have strongly hinted they will build the Camaro.

Lutz says GM wouldn't consider building the car unless it could sell more than 100,000 a year. He says the Camaro, a car he describes as "a little bit off to the side" of mainstream segments, would draw new customers and promote GM's product quality.

The Camaro would be aimed at the Ford Mustang, which sold 160,975 units in the United States last year. In the peak years of muscle-car coupes, the Camaro sold 200,000-plus units.

The Camaro would be part of GM's coming lineup of midpriced to premium-priced cars on a new rear-drive architecture developed by Holden. North American production of those vehicles is expected in 2008 or 2009.