The world's No. 2 auto maker Ford Motor Co. will battle leader General Motors Corp. for vehicle production supremacy before emerging as the victor by 2005, according to a study to be released today. For the first time since 1930, when the Model A was still rolling off the assembly line, Ford will take the top spot in the number of cars and trucks manufactured annually, while smaller auto makers will feel increasing pressures to merge. Ford production will grow to 9.15 million cars and trucks in 2005 from an estimated 7.77 million in 1999, beating GM with 9.10 million in 2005, up from 8.08 million in 1999, according to the study prepared by PricewaterhouseCoopers unit Autofacts. Autofacts' estimates included figures from auto makers controlled by another car company. Mazda Motor Corp., 33.4% owned by Ford, is included in Ford's total, for example. Isuzu Motor Ltd., in which GM owns a 49% stake, is included in GM because in Japanese law, a stake greater than a 33.4% share is considered controlling interest. Also, all of Saab, 50% owned by GM, is considered in its tally since GM effectively controls the Swedish auto maker.