MARTINSVILLE, Va. -- Tony Stewart says never. Joey Logano says late in the race. Jimmie Johnson says to protect a victory in the final laps, except, perhaps, if Stewart is behind him because of the potential consequences.

Theories on blocking and when it is acceptable vary widely in the NASCAR garage.

The topic has become a hot one since the last race two weeks ago in California, where an infuriated Stewart confronted Logano's crew and accused the young driver of blocking him late in the race.

"I don't like blocking. I never have, I never will," Stewart said at Martinsville Speedway. "It's our jobs as drivers to go out there and try to pass people. That is what racing is about. We didn't have blocking 10 years ago. I don't know where all of a sudden it became a common deal or some people think it's alright to do now and think it's common practice. I don't believe it should be common practice."

Others disagree, especially when trying to hang on for a victory.

"Those are decisions we all make on the track and when you are in the sport long enough, you realize what those decisions could lead to and, honestly, who you throw a block on," Johnson said.

"They could come back and haunt you, so as we are trying to win a race, win for our team, win for our sponsors, there are these other elements that you may not consciously think of, but there is this quick snapshot that flashes through your mind when you throw a block," he continued, adding that if you see Stewart approaching in your rear view mirror, "you probably expect something is going to happen."

Blocking can be keeping a car in front of you by continually positioning your car in front of theirs, or taking away their preferred line around the track by adopting it for yourself, even if it's not your preferred line. The thinking is if a driver is gaining on you, taking away his line can slow that.

At Martinsville, where the Sprint Cup Series will race 500 laps on Sunday, cars typically swing wide heading into the turns at each end of the track, then hug the inside curb. A blocking maneuver by a leader might cut down that wide swing, forcing a challenger to drive higher up in the turn away from the curb.

It helps to know a fellow competitor's views, and tendencies, he said.

"He has made that known over the years, so there are guys that you probably don't want to do that to," Johnson said of Stewart. "But then again, at the end of the race I feel like things go to the next level and they change and to defend for a win, you have to take some extreme measures at times."

Logano feels like he was taking those measures at Fontana, but wound up getting tangled up with Denny Hamlin, sending Hamlin into the wall, and Kyle Busch passed them both and claimed the victory.

Presented with the same circumstances in Sunday's Sprint Cup race, Logano would take into account where in the 500 laps they are, but at the end, said he'd race the same, and thinks Stewart would, too.

"Late in the race, I would probably do the same thing if it's the right move at the time, but like I said, early in the race I wouldn't," Logano said. "This is one of the toughest race tracks to get around and passing cars is hard, so patience runs low here. It's a give-and-take race, for sure."

That position, Jeff Burton said, is valuable information, as is a driver's history.

"You've got to do what you think is best. I think at the end of the day, you have to remember what you do to somebody, you have to expect it's going to be done back to you," the veteran driver said. "If you feel like what you are doing is okay and it would be OK if it was being done to you, then you do it."

It's essentially about drivers policing themselves, he said, which can get complicated with a victory hanging in the balance.

"The problem we have in our sport is we have a lot of drivers that will complain when it happens to them, but when they do it to you they look at you like, 'What's wrong?'" he said.

"Because this is a self-serving sport and we tend to become selfish people in these race cars. You've got to be open-minded and understand what's good for you has to be good for the next guy."

• Read more articles by HANK KURZ Jr.

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