Although Ford's full-size F-series pickup is still the nation's top-selling truck -- as it has been for more than 20 years -- the company has lost truck market share, some of which has been claimed by a resurgent General Motors. In fact, heading into the final quarter of the year, the two giants are locked in a dead heat for national pickup supremacy, according to the Dallas Morning News. Through August, GM had 39.36 percent of the pickup segment with its Chevy Silverado and GMC Sierra, up from 38.05 percent last year. Ford had 39.61 percent of the segment, down slightly from 39.99 percent in 2000, according to figures compiled by AutoPacific, an industry marketing consultant. The truck battles could have considerable impact on both companies, according to the Morning News. Profits from truck sales provide much of the funding for the incentives that prop up sagging car sales. And the Ford F-150 and Chevrolet Silverado couldn't have a higher profile: They are the No. 1- and No. 2-selling vehicles of any kind in the United States, and have been for years.