General Motors Corp. is hoping that "Days of Thunder" will strike lightning in its Chevrolet showrooms.

The new movie from Paramount Pictures stars Tom Cruise and the Chevrolet Lumina.

Cruise is hot. The Lumina is not -- at least not in new-car showrooms. To prop up lackluster sales, GM has had to knock $1,000 off the price of the 1990 model sedan and coupe and give away free V-6 engines (a value of $660) to people who prefer them over the standard 2.5-liter four-cylinder engine.

If that doesn't boost sales, GM is hoping its promotional tie-in with Paramount Pictures will. The automaker is spending nearly $10 million to make sure that people see the movie and the Lumina race car, according to some industry sources. GM declined to comment on its investment in the movie except to say that none of the money was spent to get Paramount Pictures, which produced the film, to actually use the Lumina.

"No one can come to us and say: 'You bought your way into this one,' " said Dave Hederich, a Chevrolet spokesman in Detroit. Paramount, instead, came to GM at the urging of actor Cruise and his friend, J.R. Hendrick III, according to Hederich and several others familiar with the development of the movie.

Hendrick owns four NASCAR race teams featuring Chevrolet Lumina cars, 31 new-car dealerships including several Chevrolet franchises, a sportswear company and a real estate firm -- all of which operate under the umbrella of Hendrick Management Corp. in Charlotte, N.C.

"The whole movie hinged on the friendship between Cruise and Hendrick," said Steve Matchett, Hendrick's assistant.

Paramount officials yesterday would not comment on the arrangement. But the upshot, according to Hendrick and Matchett, was that a deal was struck under which Hendrick "supplied and prepared all of the cars for the movie."

GM enthusiastically went along because "the movie gives the Chevrolet Lumina a starring role, too and identifies Chevrolet as a winner," said J.C. Perkins, Chevrolet's general manager.

Ford Motor Co. and Chrysler Corp. officials said that Paramount invited their companies to play bit parts in the movie, which they accepted. "They wanted to use some of our signs around the race tracks to give the movie some authenticity," said Michael J. "Mike" Moran, Ford's spokesman for motor sports. "I don't think that we're disappointed that we're not in there" with a car in the movie, Moran said. "I think we all benefit because the movie popularizes NASCAR racing."

Other companies that could reap windfall sales from the movie include Coca-Cola, Exxon, Hardee's, J.C. Penney Co. and Tyco Toys -- whose products are mentioned in "Days of Thunder" or whose emblems are emblazoned on cars or clothes in the movie.

Together with GM, those companies will spend $50 million promoting the movie.

But along the nation's auto rows, where new-car sales are running 8.4 percent below last year's levels, there is skepticism about the movie's ability to help.

"We haven't been as busy as we'd like to be," said Don Peck, president of Bob Peck Chevrolet in Arlington. "Sales have been kind of slow."

Other area Chevrolet dealers also said they have yet to see a "halo effect" from the movie on their car sales. However, Michael Friedman, sales manager at Sport Chevrolet in Silver Spring, said that his company is selling cars, including Luminas.

"We're putting 'Days of Thunder' kits on Luminas, which gives them another look, and sales are picking up," Friedman said. "The movie looks like it's going to be a hit, and our business is looking real good. We're happy."