Far West Financial, the holding company for Far West Savings & Loan in Newport Beach, posted net income of $21.8 million for 1987, a 6% decline from $23.2 million earned the previous year. Revenue rose 9.1% to $370 million last year from $339 million the previous year. Far West's fourth-quarter net income fell 75.5% to $1.2 million from $4.9 million in the previous year's final quarter, while quarterly revenue rose 5.5% to $94.75 million from $89.8 million the previous year. Total assets grew 25% to $3.75 billion at the end of December from $3 billion a year earlier. William Belzberg, chairman of Far West, blamed the lower earnings mainly on a $3.8-million write-off required by federal regulators.