Declining pickup sales and soaring gasoline prices are threatening Ford Motor Co.'s big-block V8 engine program.

Ford told suppliers last week to stop work on a 6.2-liter V8 engine that had been scheduled to go into the F-series pickup as early as next year, sources told Automotive News.

The engine was canceled for the 2010 F-150, the sources said. It's unclear whether it still is planned for the larger F-series Super Duty pickup.

The big V8 already had been stripped from the next-generation Ford Expedition and Lincoln Navigator full-sized SUVs.

The engine program, known internally first as Hurricane and then Boss, was Ford's answer to General Motors' large-displacement V8s. The program had been shelved in 2005, but Ford executive Mark Fields revived it after assuming leadership of the company's Americas unit.

Fields said last week that the program is still on but acknowledged that it has been scaled back.

"We've made a significant investment in" the Boss engine program, Fields told in an interview. "The program is moving forward but with lower volumes and only one displacement."

Fields didn't disclose the displacement of the engine that is scheduled to come to market. He also declined to identify the vehicles that would get the Boss engine. "It will be as fuel-efficient as possible," Fields said of the surviving engine.

Sources familiar with Ford's engine programs said it's possible that the automaker may assign the Boss name to a 5.0-liter V8 being developed for the Mustang. That would make marketing sense; the Boss label long has been connected to performance Mustangs.

But the picture is murky on the family of V8 engines that Ford will use for future big trucks. The F-150 currently comes with 5.4-liter and 4.6-liter V8s. The gasoline engines on the Super Duty are the 5.4-liter V8 and a 6.8-liter V10.