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With 10 to go, Mark Martin has a lead of 0.42 of a second over Jimmie Johnson and appears to have the race in hand, as Johnson doesn't seem able to get close to him. Martin is now out by nearly 10 car lengths.
With eight to go, Martin has a full second lead, and is a lock, barring a flat tire or another late caution.
Martin is home free, sailing to his second win in the past four races. The old man is back.
With 25 to go, Dale Earnhardt Jr. smacks the wall and spins to bring out the 17th caution of the night.
Johnson bids for the lead with 20 to go, but Martin holds on. Johnson tries again underneath, but still Martin holds.
With 17 to go, Martin pulls out to a lead of four car lengths over Johnson.
Now it's getting serious. The 15th caution, for debris, comes out with 320 down, 47 to go. These are the final scheduled pit stops.
The Stewart-Truex-Gordon trio should have the strength, but they've got to fight through seven cars that stayed out.
Restart with 42 to go, and this should be the sprint to the finish -- except that this is Darlington, and more possible cautions lurk at every corner.
The leaders stay out for the restart with 29 to go. Martin still leads, followed by Johnson and the onrushing Stewart.
And the 14th caution is for ... the Biff.
Greg Biffle, who has dominated so much of the evening, crashes with 72 laps to go. He's able to continue, but out of a chance to win.
Joey Logano, who went into the pits leading, has come out eighth.
Jimmie Johnson has moved back into contention, in 10th. With 61 to go, Johnson jumps into eighth place, and is on the move.
Stewart has moved into second place but isn't gaining on Truex.
David Reutimann smacks the wall hard again, but gets cleanly down to the inside, so there's no caution.
Busch takes himself out of contention by slamming the wall with 94 laps to go, but does such a good job of controlling the car that there's no caution ...
Until the next Darlington stripe, earned by Jamie McMurray, brings out the 12th caution.
All the front-runners pit, and there's another huge shuffle of the front due to two-tire vs. four-tire stops.
Biffle drops all the way back to ninth with a four-tire stop.
A restart with 281 down, but Carl Edwards brings out the 13th caution with 283 down after being nudged up to the wall by Biffle.
Green with 80 to go, the running order is Logano, Newman, Stewart, Gordon, Truex.
Sam Hornish Jr. spins on the first lap of green, but gets off the track, so no caution.
Quickly, yet another caution when Clint Bowyer crashes with 222 down.
Green with 225 down. Now how many laps can we go without another caution?
Maybe the flagman's arm is getting tired. With 229 down David Reutimann scrapes the wall and causes a swerving logjam behind him, but they're allowed to continue under green.
Greg Biffle, who led so much through the middle stages, is now stuck back in seventh due to his team's decision to take four tires while Truex took gas only and Kyle Busch took two.
The flagman gathers his strength back, and throws the 11th caution -- the first of the night for simple debris -- with 249 down.
There's a mixed bag pitting. Biffle stays out, along with Truex who moves into second, McMurray who moves to third, and Kyle Busch to fourth.
A restart with 189 down, and finally Biffle is having trouble shaking somebody -- Truex. The Biff can't get his lead back to one second by the time another -- yes, the eighth -- caution comes out on Lap 189 when Ragan wrecks again.
Another restart with 201 down, and this time Biffle begins to build a cushion on Truex.
And the cautions just keep on coming. Kurt Busch spins off Turn 4 with 215 laps down to bring out the ninth one.
This time the leaders pit, and Truex goes with fuel only to get out of the pits first. Biffle takes four tires.
Truex takes the lead, followed by Kyle Busch, who had a two-tire stop.
Jimmie Johnson, who fell a lap down when caught by an earlier caution in the pits, has been turning the fastest laps on the track but is still stuck in 17th.
Jeff Gordon, who was running up front until an unscheduled pit stop for a flat tire dropped him to 32nd, has managed to work his way back to 28th.
The green flies with 165 down, and Biffle moves easily out front again. Stewart is the only one who can hang near the Biff, and Stewart is more than a second behind by Lap 169. By 175, Biffle is pushing back out toward a comfortable four-second lead.
Sam Hornish Jr. brings out the race's fifth caution on Lap 118 with a spin off Turn 2.
The leaders pit under this yellow. Biffle comes out first, followed by Stewart, Truex, Matt Kenseth and Kahne.
Bobby Labonte stays out to inherit the lead, but relinquishes by pitting after he scores the five bonus points.
Jimmie Johnson is back on the lead lap after being caught in the pits under an earlier caution, and teammate Jeff Gordon, who lost a lap with an unscheduled stop for a flat tire, is in position to get the next free pass onto the lead lap.
Restart on Lap 123, and Biffle flashes away from the rest of the field, with Stewart second and Truex third.
Biffle is checking out now, with more than a two-second lead over Stewart by Lap 130.
Biffle is gunning for his third win in the past five races here, having won in 2005 and '06.
Jeff Gordon pits, unscheduled, on Lap 99 with what appears to be a cut tire. A four-tire change drops him all the way back to 32nd, one lap down.
That's a big impediment to Gordon's designs on surpassing Cale Yarborough in Southern 500 victories. They have five apiece.
Gordon also was hoping to tie Yarborough in career victories tonight, with 83.
Kasey Kahne takes the lead on Lap 72.
Michael Waltrip brings out the night's fourth caution -- and his second -- when his engine blows, he smacks the wall and his car catches fire. He's OK, but at this pace we could be heading for the 24 Hours of Darlington.
Restart comes with 85 laps down.
Truex passes Gordon for second on Lap 87, but Gordon tucks right in, poised to repass.
The race goes green again with 37 laps down and Ryan Newman in the lead.
By Lap 49, Jimmie Johnson is challenging Newman for the lead again, but Newman holds on.
Johnson got to the front by staying out under the second caution, but is on decent tires because he did pit under the first caution -- then with nothing to lose because he was in the back anyway.
A quick game of bumper cars brings out the third caution with 31 laps down, as Casey Mears gets sideways and into the wall, collecting A.J. Allmendinger. Denny Hamlin gets through with a slight scrape.
Mears appears to have gotten the worst of it, as the right front of his car smacks the wall. But Allmendinger and Kurt Busch also pit for repairs.
Robby Gordon gets the first legitimate Darlington stripe of the evening, scraping the wall in Turn 2 but continuing, so there's no caution.
Jimmie Johnson stays out as the leaders pit, and inherits the lead already after starting at the back. Kenseth and Gordon are now fifth and sixth, respectively, as the green flag flies with 24 laps down.
At the command to start engines, there are some scattered empty seats, mainly in low rows where it's hard to see around the track. Alas, it appears the Lady in Black has fallen short of her fifth straight Mother's Day weekend sellout.
NASCAR's out-of-the-blue announcement of substance-abuse suspensions for driver Jeremy Mayfield and two crewmen from other teams shook up what had been a hot, sleepy prerace afternoon at Darlington.
Turns out NASCAR just got the test results back at noon today, off random testing conducted last weekend at Richmond, Va.
Mayfield becomes the first Sprint Cup driver suspended under NASCAR's current policy. But he had failed to make the field in time trials Friday, so his absence won't affect the Southern 500 tonight.
NASCAR would not reveal the types of substances involved, but vice president Jim Hunter did rule out alcohol in all three cases.
Also suspended were Tony Martin, a crew member on the No. 34 car to be driven tonight by Tony Raines, and Ben Williams, a crewman with the No. 16 Nationwide car alternately driven by Greg Biffle and Matt Kenseth.
Former Nationwide driver Kevin Grubb, who was found dead of an apparent self-inflicted gunshot wound last week, had been suspended under NASCAR's substance abuse policy.
Former Nationwide driver Shane Hmiel remains under indefinite suspension for violating the sanctioning body's substance abuse policy, as does former Truck driver Aaron Fike, who has admitted having used heroin.
Although Mayfield is the first Cup driver suspended under NASCAR's new policy, Tim Richmond was the first held out of a race for a supposed substance violation.
Richmond was barred from the 1988 Busch Clash, now known as the Bud Shootout, after he tested positive for undetermined substances. But upon further analysis, NASCAR announced that the substances were legal over-the-counter pain relief medications.
Richmond later sued NASCAR over the incident, but the matter was settled out of court and the agreement sealed. Richmond died of AIDS in 1989.
If the Southern 500 can't go back to Labor Day, then Labor Day will come to the Southern 500.
That's the way the weather has felt this afternoon, waiting for the 7:30 p.m. start. The forecast is for highs in the 90s. If not for a slight breeze, the garage area would have been like an oven from the time it opened at 2 p.m.
One major reason the race has sold out all four previous years it has been run on Mother's Day weekend is the usually gorgeous South Carolina weather in May, according to Darlington Raceway president Chris Browning.
But this time the heat might hurt his chances for a fifth straight sellout. Due to the bad economy, Darlington needed a strong walk-up crowd today to complete a sellout.
Pearson, 74, was sitting on a golf cart near the garage area when Yarborough, 70, arrived with an entourage of his sons-in-law and some grandchildren.
"There's old man Pearson over there!" Yarborough cracked to his family.
Pearson jumped up and began posing for pictures with two of Yarborough's grandsons, and when Yarborough tried to join in, Pearson told the boys, "No, you don't want him in here."
Who was better here?
"I'll have to admit David won 10 and I only won five, so that speaks for itself," Yarborough said. "I never could win the spring race. David could win all the spring races, and for some reason, I had some problem every spring."
Yarborough recalled the time the old Lady in Black threw him clear out in the parking lot, during a race in 1965.
"I was green, and a really young driver named Sam McQuagg was coming up," Yarborough said. "Sam and I had been racing together for quite a while. I'd been trying to get around him, and trying to get around him, and finally, coming down the frontstretch, I got far enough up beside him that I thought he'd back off and let me go."
Single file was the only way they could enter the old Turn 1, now Turn 3, at Darlington.
"But he didn't," Yarborough continued. "Sam and I got tangled up and my car just got airborne for some reason, and went over the hood of Sam's car and completely over the guardrail. I never touched the guardrail."
Even in midair, "I was still trying my best to drive that thing," Yarborough said. "But when I looked down and saw grass, I knew I was in trouble then. I knew there wasn't any grass on that racetrack."
Yarborough walked away with bumps and bruises. "It was a hard lick," he recalled. "The car was completely destroyed except right where I was sitting."
It was easy for Yarborough to describe to his grandsons where he landed that day. His parking pass today was for the media lot in precisely the spot where he landed in '65.
Somebody asked Pearson, likely the most common-sense NASCAR driver ever, what he would change about today's rules.
"I'd change all of 'em, if I had anything to do with it," Pearson said. "Because I don't like none of 'em."
Sitting around with former driver and lifelong Darlington aficionado Buddy Baker, I got this musing from him: "Wonder if Harold Brasington ever, ever thought the front would be the back, and the back would be the front."
Brasington was, of course, the country visionary who built Darlington Raceway in 1950 as NASCAR's first superspeedway.
The frontstretch and backstretch were switched in 1997, to accommodate larger grandstands. The old main grandstands back up closely to the four-lane Harry Byrd Highway, so there was no room for expansion.
What used to be the backstretch had woods behind it, so bigger grandstands were built there, and the start-finish line was moved in front of the new seats.
"Whenever I talk about going into 1, I still mean over there," Baker said, pointing toward the old Turn 1 at the narrow end of the track.
Ed Hinton is a senior writer for ESPN.com. He can be reached at firstname.lastname@example.org.