BANKING

First Interstate Acquiring Texas Bank Firm: Continuing its buying spree, First Interstate Bancorp will acquire Austin, Tex.-based BancWest Bancorp and its principal subsidiary Bank of the West for $35.8 million in cash. Due for completion in the second quarter of 1994, the purchase of the Texas bank is the bank holding company’s fourth major bank purchase of 1994. Bank of the West, a six-branch, $248-million-asset institution, would be blended into First Interstate Bank of Texas, the state’s fifth-largest bank. First Interstate is also parent of First Interstate Bank of California.