Drivers who tested their cars in January at the revamped Las Vegas Motor Speedway will find much different conditions when they attempt to qualify today. Eighteen teams will vie for seven spots in Sunday's race under sunny skies and temper- atures near 80 degrees. Photo by John Gurzinski. Joe Nemechek is one of 18 drivers who will attempt to qualify today for one of seven spots in Sunday's UAW-DaimlerChrysler 400. Photo by The Associated Press

Today's qualifying is the biggest race of NASCAR weekend for 18 Nextel Cup teams.

Fifty-four teams have entered UAW-DaimlerChrysler 400, but only 36 are ensured spots in Sunday's starting field of 43.

Today, the 18 drivers contending for seven open positions need to earn their way into the 267-lap race -- they'll get only two laps to qualify.

Qualifying is scheduled to begin at 3:10 p.m.

As a former series champion, Dale Jarrett is guaranteed a spot in Sunday's race. Based on last year's point totals, 35 other drivers are also ensured spots and will try to lock up good starting positions.

Joe Nemechek should be worrying only about going for the pole.

But that's not the case.

The No. 01 Chevrolet Nemechek drove for Ginn Racing a year ago finished the season safely 28th in points. But that car has been handed to Mark Martin.

Nemechek, now in Ginn's No. 13 Chevy, is seventh in points this year, but those points have no value this week.

Only after the fifth race -- in two weeks at Bristol, Tenn. -- are spots determined by this year's points.

"Once you qualify, it's like winning a race," Nemechek said. "The pressure is immense -- no other way to say it. There is so much effort and money put into the program that you never want to let down your teammates and sponsors. Never."

The pressure is on the struggling Toyota teams to show well in Las Vegas.

Jarrett, 28th in the points standings, drives the No. 44 Toyota for owner-driver Michael Waltrip.

Dave Blaney, 42nd in the standings, drives the No. 22 Toyota for Bill Davis Racing. Blaney has been able to race off the car's success last year, when it was 27th in the standings.

Of the seven Toyota drivers, only David Reutimann of Waltrip's team has earned his way into both races this year.

Waltrip and Brian Vickers have each started one of the two. Former open-wheel star A.J. Allmendinger, Vickers' teammate, has yet to qualify.

"We went into California with the mind-set that we first needed to qualify and second needed to run all of the laps in the race," said Vickers, who is in 34th place after two races this year.

"These small goals are important, but there's also a bigger picture we're looking at here -- and that's to make sure we're locked into the top 35 in points after the first five races. We've got three races to go, and anything can happen."

Just about everything has happened to Waltrip, and most of it has been bad.

Waltrip, in 46th place, drives the No. 55 Toyota. He finished 30th in the Daytona 500 but did not qualify for the California race.

He also started the season with a 100-point penalty after NASCAR determined before the 500 that the engine in his car had an illegal fuel additive.

The other Toyota driver, Jeremy Mayfield, must qualify based on speed because he did not qualify for Daytona or Fontana.

One rookie guaranteed a starting position Sunday is Jon Wood, who will take over the No. 21 Wood Brothers Ford for his first Cup start.

Ken Schrader drove the car last year and finished 33rd in points. He's driven it twice this year but will be in a different Wood Brothers car.

Schrader must qualify because it's the first race for the new car.

There won't be as much drama during today's 5 p.m. Sam's Town 300 qualifying session. Based on the 44 entries received for Saturday's Busch Series race, only one car won't make the field.