The plant, near Philadelphia, employs 900 people and makes mostly automobile tires, B. F. Goodrich Co. said. The closing, which will begin in April, fits in with the company's restructuring plan that had been announced in June, the company said. The plant, which began production in 1937, is the smallest, oldest and least efficient of the company's tire plants, tire group President Robert A. Eisentrout said. Goodrich has hired a placement firm to help the Oaks workers find other jobs. Once the plant is closed, employees will also be eligible for extensive supplemental pay benefits and medical coverage for up to two years, the company said.