Among the entries in Saturday's Busch Grand National race at Daytona International Speedway are the Cellular One Pontiac, the Nestle Nesquik Ford and the TBA Chevrolet.

That's TBA, as in "To Be Announced," signifying yet another stock-car racing team trying to compete in NASCAR without a corporate sponsor to underwrite its expenses.

No sport enjoyed more explosive growth in the go-go economy of the 1990s than NASCAR, which built racetracks and added events in such major markets as Dallas, Las Vegas and Southern California. Attendance boomed, TV ratings soared and overnight stock cars became Madison Avenue's vehicle of choice for showcasing its advertising messages.

But like virtually every other business, stock-car racing is feeling the pinch of a constricting economy these days. And it's increasingly evident both on and off the track as corporations spend less on entertainment, leaving blocks of tickets unsold and luxury sites unleased; racetrack owners lose event sponsors, with last season's MBNA 500, for example, now simply called the Atlanta 500; and race teams fold after losing sponsors, which happened to the Kmart Ford when the retailer filed for bankruptcy last season.

"It ain't good," said driver Kenny Wallace.

But no disappearance from the NASCAR landscape would be more striking than that of R.J. Reynolds, whose Winston brand has sponsored stock-car racing's major series since 1971. That was the year the federal government booted tobacco advertising from TV. And cigarettes and NASCAR have been linked ever since, with the sport providing a vehicle for cigarette-makers to sneak back into American living rooms as NASCAR's series sponsor.

The alliance reaped dividends for both. Backed by RJR's ad dollars and marketing expertise, NASCAR upgraded its dilapidated tracks, erected mammoth superspeedways, pumped millions into the championship fund and painted its grandstands Winston-brand red and white. RJR, in return, got its major brand's name back on the air and reached millions through trackside billboards and promotions.

Speculation surfaced a decade ago that further governmental restrictions would send tobacco packing for good. At the time, with NASCAR enjoying unparalleled growth, it seemed corporations would trip over themselves to take RJR's place -- with Coca-Cola and McDonald's rumored among them.

But in the wake of RJR's recent acknowledgement that it would step aside if a new sponsor could be found, citing the fact that "business dynamics have changed dramatically," no suitors have surfaced.

While many lament the eventual loss of RJR, even seven-time Winston Cup champion Richard Petty sees a potential silver lining.

"RJR took the sport out of the South," Petty said. "You hate to leave the people that got you to this dance. But under the things they have to do according to the government, they can't take us into a lot of new places because the government won't let 'em."

NASCAR CEO George Pyne said there is no urgency to replace RJR, given that the company has vowed to honor its recently signed five-year sponsorship extension.

"While we're sad to see them go, at the same time, change and challenge bring opportunity -- to have a title sponsor that can buy TV ads, buy radio ads and market to families," Pyne said.

Meantime, many mid-tier race teams are looking for backers, particularly on NASCAR's Grand National series, where fewer than 20 teams have sponsorship to run the full season.

The broader fear is that if corporate dollars continue dwindling, the competitive gap between racing's haves and have-nots will increase.

Racing's economic slowdown starts with the slump in advertising, which is down 10 to 20 percent by most estimates, while the cost of racing keeps soaring. There's no cap on spending in motor sports. And teams that can afford it will spend whatever they can in search of speed -- investing millions in wind-tunnel tests and the development of lighter, more powerful engines.

"Back when it cost $5 million to run a Winston Cup team, a lot of corporations could afford it," said driver Todd Bodine, who lost his job last year when Kmart pulled out. "But now these guys are asking for $12 million, which is absolutely astronomical. Not a lot if corporations can do that."

Bodine is among the lucky ones. His team has regrouped with the backing of the National Guard, which is using his Ford as a rolling recruiting tool, and he will start sixth in Sunday's Daytona 500.

Pyne, the NASCAR executive, says the sport remains a compelling buy for corporate America, delivering TV ratings second only to the NFL and accounting for 17 of the 20 largest sporting events in the country.

"By any definition we've got significant size and scope," Pyne said.

Glen Reid, a leisure analyst for Bear, Stearns & Co., Inc., believes NASCAR will continue to fare well despite the shrinking economy.

"Companies can't afford to just stop marketing and advertising altogether, but they become more selective and more price-conscious," Reid said. "NASCAR's TV ratings have held up relatively well. Particularly the Winston Cup events are all very well attended. A lot, if not most, are sold out. I think companies still view this as a pretty good bang for the buck."

So far, just the mid-level teams are feeling the pinch. Drivers such as Jeff Gordon (DuPont), Dale Earnhardt Jr. (Budweiser), Dale Jarrett (UPS) and Mark Martin (Viagra) are still bringing in annual sponsorships in the $16 million range.

"The smaller sponsors aren't here anymore," said team owner Felix Sabates, whose backers include Coors Light, Target and Havoline. "But the big sponsors are still here."

So are individual ticket buyers, according to Ed Clark, CEO of Atlanta Motor Speedway. The Atlanta track is still seeking a title sponsor for its spring Winston Cup race, and attendance is running about 80 percent due to a slowdown in group sales. But sales to individuals are holding steady.

"Even though unemployment may be a little higher, they're still coming to the events," Clark said. "The races are their getaway from the daily problems and things like that."

But that hasn't helped car owner Andy Petree, a former champion crew chief. His two-car operation ran into funding trouble last year. Dallas Cowboys owner Jerry Jones expressed interest in forming a partnership, but backed out after realizing all the best drivers were locked into long-term contracts.

"I could get down on it some, but I've got a lot to offer: A championship crew chief and a winning car owner," Petree said. "It's just not enough right now."

He was forced to lay off roughly half his 58 employees in the offseason and arrived at Daytona with one car, a skeleton crew and limited backing from Monaco Coaches. Driver Christian Fittipaldi, nephew of open-wheel legend Emerson Fittipaldi, qualified the car 34th in Sunday's Daytona 500.

"I'm definitely at the crossroads," Petree said. "I just hope we do well. We could do a lot more if we just had the right backing."

Meantime, the only thing Petree can do is look backers and hope the economy turns around.

Said Wallace: "Who ever thought that Kmart would go under? Who ever thought that smoking would go under?"

Racing Note: Rusty Wallace will start 38th in the Daytona 500, rather than eighth, after being penalized by NASCAR officials for having an illegal carburetor in his Dodge during Thursday's 125-mile qualifying race. Wallace will forfeit his prize money of $28,720, and crew chief Bill Wilburn has been fined $10,000.

Driver Todd Bodine, sponsored by the National Guard, lost his job last year when Kmart pulled out. "Smaller sponsors aren't here anymore," one owner said.