SPRING HILL, Tenn. – General Motors is bringing back hundreds of idled workers to build a new generation of four-cylinder engines at the Tennessee plant where the Saturn brand was launched two decades ago.

But GM North America President Mark Reuss said production of any new car at Spring Hill remains uncertain — much like the economy.

“As we rebuild the company, we have to feel comfortable about where the economy is and people have to have confidence in the economy and that will dictate how we reinvest and where we reinvest,” Reuss said.

About 480 workers will be recalled as GM plans to invest $483 million to build the next generation of the company’s Ecotec four-cylinder engine. The plant already builds three four-cylinder engines.

The automaker laid off about 2,000 workers at Spring Hill last year and about 800 of those workers have relocated to GM plants in other states.

About 1,000 retired, active and laid-off workers gathered Friday to hear from GM officials, Gov. Phil Bredesen and others. Also present were U.S. Sens. Bob Corker and Lamar Alexander and U.S. Reps. Marsha Blackburn and Lincoln Davis.

Bredesen sounded an optimistic note about the future.

“This is such a good plant,” he said. “As the automotive market comes back, there’s no question in my mind that this Spring Hill plant has a role to play in the future.”

A handful of boos erupted from the workers when Corker showed up. They apparently were still upset over Corker’s opposition to bailouts for the auto industry and his push to get the United Auto Workers to agree to wage and benefit concessions.

“I do understand the reaction today, but on the other hand I play a major role in the debate as it relates to the auto industry in this country and I know that debate has helped shape the auto industry and make it stronger,” he said.

The company received a $50 billion government bailout and so far has paid back $6.7 billion and has a plan to start the process of selling stock to the public.

Mike Danford, 47, was laid off last year and lauded the worker recall.

“I’m like a little kid on Christmas,” Danford said, adding that he is optimistic about a car line coming to the plant in the future. “I believe we will have a vehicle here in the next couple of years.”

Spring Hill Mayor Michael Dinwiddie said he’s just glad to see people going back to work.

“How awesome it’s going to be for hundreds of people to say, ‘I have a job’,” he said.