General Motors is bringing back 480 idled workers to build a new line of four-cylinder engines at the Spring Hill plant in Tennessee. However, the company says it is uncertain if it will be producing any new cars.

According to GM, the employees will be recalled as GM invests $483 million in its Ecotec four-cylinder engine line. The plant already builds three four-cylinder engines.

GM 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, according to the Associated Press.