FONTANA, Calif. -- Sunday's Auto Club 500 marks the first time the Nextel Cup teams will use unleaded fuel.
Doug Yates, co-owner of Robert Yates Racing and one of the most respected engine builders in NASCAR, has concerns about making the switch in a 500-mile event.
"Unleaded fuel is a big change for these engines," Yates said. "Taking the lead out takes away some of the cushion, some of the lubricity of it. So we can have problems with the valves. We've been through a process of trying to find the right coatings to protect the valves from wear."
"We probably limit the mileage we run this weekend," Yates said. "We'll limit the practice time so we can inspect the engine components and make sure we're prepared. It's 500 miles, so it's a concern to make sure we get to the end."
The Busch and Craftsman Truck Series started using unleaded fuel last season, so Yates said they've learned from those events. But the Busch and Trucks series don't race 500-mile events.
Yates said the horsepower output won't change, but fuel mileage is a bit of an unknown.
"It may be a little less for everybody while trying to get acclimated to the new fuel," he said. "This event often comes down to a fuel-mileage race, so we're conscious of that and trying to get as close to our usual fuel mileage as possible."
Let 'em race
Count Elliott Sadler and Casey Mears among the drivers who believe NASCAR did the right by waiting to throw the yellow flag until after Kevin Harvick and Mark Martin crossed the final line of the Daytona 500.
"This is our Super Bowl,' Sadler said. "Let the boys race for the win. It was the big game on the big stage. It ended up being a great finish. They didn't have to go through the wreck."
The question is whether the delayed caution compromised safety and caused a bigger accident.
"I don't think anybody would have done anything any differently," Mears said. "Everybody that wrecked was going to wreck anyway. You've got a bunch of hungry guys out there with the checkered flag in sight. Even if the caution comes out, you're hesitant to check up."
Bobby Hudson, the spotter for Carl Edwards and the No. 99 Ford, suffered a heart attack Thursday night. He remains hospitalized in North Carolina.
"If anybody can make it through something like that, it's Bobby," Edwards said. "He's about the toughest guy you could meet. All our thoughts are on Bobby today."
No threats allowed
Here's a penalty you don't see every day. Richard Riley, Craftsman Truck Series crew member of the No. 88 Chevrolet, was fined $5,000 by NASCAR on Thursday and suspended for six events for threatening bodily harm to a NASCAR official during the race at Daytona last week.
Terry Blount covers motorsports for ESPN.com. He can be reached at email@example.com.