Alabama Trust Fund, Mobile, plans to add a $160 million international core equity portfolio, said Anthony Leigh, deputy state treasurer. It is a new asset class for the $2.5 billion fund, which was begun in 1981 with payments from oil-drilling companies working off the state's coast. The fund is evenly split between active domestic equity and active domestic fixed income, and executives want to diversify into international equity, said Mr. Leigh. Funding will come from both domestic equity and fixed income. A manager should be selected by the end of the second quarter. Callan Associates is assisting.