Ford Motor Co., looking over its shoulder at a growing crop of pickup rivals, will invest $1 billion to $1.5 billion to revamp its top-selling F-Series truck, according to the Detroit Free Press. Jim Padilla, head of Ford's North American operations, told the Financial Times that Ford will spend about $7 billion a year to develop cars and trucks. The F-150 is expected to receive a major refreshing but perhaps not a full redesign next year as a 2004 model, according to industry analysts. Ford spokesman Jim Bright confirmed the spending figures but would not comment on timing for the new truck. The F-Series, which includes the F-150, has been America's best-selling vehicle for 20 years and best-selling truck for 25 years. Thanks in part to zero percent and low-interest financing and other incentives, the F-Series sold a record 911,597 units last year. That's the most for any car or truck since 1972, when the Chevrolet B-cars, including the Impala and Caprice, racked up more than a million sales.