An investment group headed by J. A....

An investment group headed by J. A. Frates reported that it has increased its stake in Kaiser Aluminum & Chemical to 18.6% from 15.7% . . . Golden West Homes said it has entered into an agreement to be acquired by GWH Holding Co., an affiliate of William Lyon Co. . . . Mazda said it plans to build research and development facilities in Los Angeles and Detroit by late 1987.