The City Council has authorized its redevelopment agency to undertake studies to find out if moving a proposed freeway interchange westward would save the stalled Southeast Development Project. City Manager Lloyd de Llamas said Trans-Pacific Development Co., which wants to develop the 45-acre project for commercial use, has offered to contribute up to $100,000, or half the cost of the studies. The project, which includes construction of an interchange at Greenwood Avenue and the Pomona Freeway, is on the site of the Operating Industries landfill in Monterey Park. The state Air Quality Management District has refused to allow the city to move 158,000 cubic yards of trash from one area of the landfill to another to accommodate the project. De Llamas said the amount of trash that must be moved could be cut in half if the interchange site were moved westward. The new studies will examine the practicality of moving the interchange and explore options for moving the trash.