With sales of light trucks and SUVs flagging, the Chrysler Group plans to cut 250 jobs next week at its Detroit plant that builds standard eight-cylinder engines for the Dodge Durango and Jeep Grand Cherokee and other vehicles, local UAW officials said. The job cuts -- which will trim the work force at the Mack I engine plant to 530 employees -- come amid challenging times for the Auburn Hills automaker. The Chrysler Group is expected to unveil a restructuring plan in mid-February that's likely to include cost-cutting measures including layoffs, plant closings and shift eliminations. While no one questions that Chrysler's truck-heavy lineup is suffering in showrooms, some union officials who spoke to The News on the condition of anonymity said the automaker appears to be taking a hard line with the United Auto Workers. Chrysler would not confirm the layoffs nor would the company comment on reports of similar cuts at Detroit Axle and an Indiana plant that makes transmissions for the Dodge Ram and Dodge Dakota pickups. Sales of both vehicles are stagnant. "We continue to evaluate our operations in an effort to remain competitive," said Michelle Tinson, a Chrysler Group spokeswoman. "Achieving operational efficiencies at our manufacturing sites is a common occurrence. As stated previously, the company will announce restructuring actions once approved by the board of management."