Updated

It's the third race of the season for both the NASCAR Sprint Cup and Nationwide Series this weekend at Las Vegas Motor Speedway.

NASCAR

Sprint Cup Series

Kobalt 400 - Las Vegas Motor Speedway - Las Vegas, Nev.

This weekend's Sprint Cup Series race at Las Vegas Motor Speedway will be the first of 11 events contested on 1.5-mile racetracks this season.

NASCAR has a new rules package for the intermediate tracks on the Sprint Cup schedule. Forty-eight teams participated in a four-hour test session on Thursday at Las Vegas, familiarizing themselves with the 2014 package.

Rule changes for the intermediate tracks this season include statically setting the race car ride height and eliminating the pre-and-post-race front- height rules and inspections. The package also contains a square leading edge on the splitter, side-skirt and rear-fascia adjustments and an eight-inch rear spoiler. A 43-inch by 13-inch radiator pan are among the changes as well.

NASCAR implemented chassis and aerodynamic adjustments into the setup specifications, with the hopes of creating more green-flag passing and side- by-side racing. The sanctioning body gathered information from lengthy test sessions held at Charlotte Motor Speedway, a 1.5-mile track, in October and December.

"For the most part, I think it looks like there's speed in the cars, and I think as the weekend unfolds [at Las Vegas], they'll probably be a little bit quicker," NASCAR vice president of competition Robin Pemberton said. "I think the important day will be Saturday [final Sprint Cup practice] where we have more cars working on race trim and around each other. It will be about learning the aero part of the car, how they drive around each other. That will probably change significantly from multi-car runs to single-car runs."

Fresh off of his win last Sunday at Phoenix International Raceway, Kevin Harvick topped the speed charts in testing at Las Vegas. Harvick, in his first season as driver of the No. 4 Chevrolet for Stewart-Haas Racing, made a total of 42 laps. His best lap was clocked at 190.140 mph. He was the only driver who surpassed the 190 mph mark.

"I thought it went really well," Harvick said of his test session. "We struggled in the beginning just to get the feel. It took us a couple of hours to kind of get everything situated and get the balance of the car right. Then we felt pretty good about it after that. Changed a lot of stuff and did a lot of different things to the car. I felt like we made good head way in the end, and hopefully, we can progress on that and make it even better."

Harvick drove for Richard Childress Racing during his first 13 seasons in the Cup Series before moving over to SHR. He has yet to win a Cup race at Las Vegas but finished second there in 2010.

Rookie Austin Dillon had the second quickest lap during the Las Vegas test. Trevor Bayne was third, followed by Ryan Newman and Danica Patrick, who is Harvick's teammate at SHR. Dale Earnhardt Jr., the current points leader and winner of the season-opening Daytona 500, placed 19th on the speed charts.

"Whatever we use here will traditionally translate to a lot of racetracks throughout the year," Earnhardt said. "We may be able to see trends. We have a lot more spoiler on the car with the new package, on the ride height, that changes the downforce quite a bit. So you're going to start to see trends whether it be rear-spring split, different things that will be a little bit different from last year that will help you shortcut understanding how to take it to another racetrack."

Both Earnhardt and Harvick will make it into this year's Chase for the Sprint Cup championship unless there are more than 15 different winners in the first 26 races (regular season). That's only happened twice in the 65-year history of NASCAR's premier series.

During the offseason, NASCAR made sweeping changes to the Chase format by expanding the field of drivers/teams from 12 to 16. The top-15 drivers with the most wins over the first 26 races will become eligible for the playoffs, provided they have finished in the top-30 in points. The 16th and final position will go to the driver who is the highest in points without a victory.

Could there be a third different race winner this season on Sunday at Las Vegas?

One year ago at this track, Matt Kenseth gambled on tires late in the race and then held off Kasey Kahne in the closing laps for the win. It came in just his third start as driver of the No. 20 Toyota for Joe Gibbs Racing. Kenseth also celebrated his 41st birthday on the day of his Las Vegas win.

Forty-eight teams are on the entry list for the Kobalt 400.

Nationwide Series

Sam's Town 300 - Las Vegas Motor Speedway - Las Vegas, Nev.

There are four racetracks currently on the Nationwide Series schedule where Kyle Busch has yet to win a race.

Las Vegas Motor Speedway, his hometown track, is one of them.

Last Saturday, Busch won a Nationwide race at Phoenix International Raceway for a record third straight time, even though the scheduled 200-lap event there was cut short by 32 laps due to rain. He also earned his record- extending 64th career win in the series.

Busch has competed in the Nationwide race at Las Vegas each year since 2004, finishing second there two times (2007 and '13). In last year's event, Sam Hornish Jr. grabbed the lead from Busch with 48 laps remaining and then held off Busch after two restarts within the final 15 laps. It was the second career win for Hornish in Nationwide.

"We had a good finish last year [at Las Vegas], considering we started further back in the pack than we wanted to, due to qualifying being rained out, so just had to work our way through the traffic," Busch said. "Got a second out of it, but would like to improve on that obviously. We are off to a good start with the Phoenix win. Just hope we don't get wet with any more rain."

There is no chance of rain in the forecast for the Las Vegas area on Saturday.

This season, Busch and Hornish are sharing driving duties in the No. 54 Toyota for Joe Gibbs Racing. Busch is scheduled to drive it in 26 Nationwide races, while Hornish will behind the wheel in the remaining seven events.

Busch won a Sprint Cup Series race at Las Vegas in 2009.

"Vegas always means a little bit more pressure - more pressure on myself - just because it's the hometown and you want to win there."

The last two Nationwide races as Las Vegas have been won by series regulars. Hornish did it last year, and Ricky Stenhouse Jr. did so in 2012. Stenhouse graduated to Sprint Cup in 2013.

Regan Smith, the current points leader and winner of the season-opener at Daytona International Speedway, has four Nationwide starts at Las Vegas, with his best finish of seventh occurring this past season. Smith holds a five- point advantage over Trevor Bayne, while Elliott Sadler trails by six markers.

Forty teams are on the entry list for the Boyd Gaming 300. Dale Earnhardt Jr., Matt Kenseth, Brad Keselowski, Kyle Larson, David Ragan and Busch are those Sprint Cup regulars scheduled to compete in this race.