INDIANAPOLIS -- The revelation came shortly after the race two weeks ago at Chicagoland Speedway, an event where two Evernham Motorsports drivers finished deep in the field and another failed to qualify. In meetings over the ensuing days, Ray Evernham finally began to get a picture of why cars that had won six races and eight poles the season before seemed so woefully off the pace.

They weren't just off. They were wrong.

"We were basing a lot of our decisions off information that was not correct," he said Friday at Indianapolis Motor Speedway, site of Sunday's Allstate 400 at the Brickyard.

According to Evernham, the team made changes to its simulation software and the aerodynamics of its Dodge racecars after a preseason Nextel Cup test session at Las Vegas Motor Speedway. The team built all of its Chargers based on that information, which no one realized was fundamentally flawed until last week. The cars that were being developed in the Evernham engineering lab proved to be nothing like the cars on the racetrack, and the performance level plummeted as a result.

"We basically have spent half a year trying to a build a foundation that didn't exist. The information we had was nonexistent. We had to go back to doing things the normal way and throw cars in the wind tunnel to find out that there was a huge difference, and we didn't have what we thought we had," Evernham said.

"It's got us far behind. Everything we did this year basically with the '07 cars is useless."

It's been a frustrating season for Evernham, who won a season-high six races last year with driver Kasey Kahne. Entering the Brickyard, driver Elliott Sadler sits 23rd in points and Kahne 25th, without a single top-five finish between them. Third driver Scott Riggs is 37th in points, and has failed to qualify for four events. The decline came as Evernham, a former champion crew chief, turned the competition end of his organization over to others in order to better oversee the business side of the race team.

Now, beginning at Indianapolis, changes are afoot. The Evernham team has decided to scrap the 2007 Charger and go back to the 2006 model that Kahne wheeled to such success last season. Former technical director Eric Warren, Evernham's engineering ace since 2002, has been placed on leave. Replacing him for the time being are vice president of competition Sammy Johns and the team owner, who's been forced to step away from sponsor contracts and business deals and get his hands dirty again.

"In the end, when you have people who are responsible for performance, and the performance is way off, you have to make changes with those people," Evernham said. "We had to face some difficult changes. Sometimes those things don't go the way people want them to. But ultimately, aerodynamically and simulation-wise were the responsibility of the engineering department, and that was led by Eric Warren. If you're a football coach or a college coach and the team is losing, ultimately you have to make changes in the areas of responsibility."

Evernham believes those changes can result in improved performance as soon as this weekend. His drivers hope he's right.

"We're the same organization that won the most races and the most poles last year," Sadler said. "We've got guys who know how to get it done. We didn't really lose anybody over the winter. We know how to get it done. ... We just kind of missed it a little bit, and sometimes that happens."

Added Kahne: "We knew at some point it would be fixed. Hopefully this weekend, we've made some gains and are closer. It's tough to say until you get on the track, but I know we've made some improvement engine-wise and aero-wise. Hopefully that will be the ticket."

Evernham said Riggs hasn't had a fair chance because of the cars he's been given, adding that "the issues they're going through with the 10 car are not 100 percent Scott's responsibility." And then there's former developmental driver Erin Crocker, whose career stalled after she began dating Evernham last year. The best thing for her, Evernham said, might be to move to another organization.

"I don't think it's any secret my personal relationship with her has hurt her career. The proper thing to do, and what I would like to do, is move her to another race team," he said.

"If I say to somebody, 'I think she's got talent, you should sponsor her,' my credibility is not good because of the personal relationship. I believe in her. We're trying to support her through her ARCA program. She has a lot of things going on, and hopefully something will open for her. She's talked to some Busch teams and Truck teams. Again, I feel like she's even a role model for female drivers. She can get the job done. The best thing for us to do, personally and professionally, is to help her go with another race team."

The struggles and consequent changes have forced Evernham to delve back into the competition end of his race team, leaving unresolved financial loose ends like a possible sponsorship deal with Budweiser and a partnership with Montreal Canadiens owner George Gillette. Evernham said the deal with Gillette should be completed within the next two weeks, and it will free him to place his total focus on competition. After the events of the last six months, that's where it needs to be.

"Quite honestly, the bottom line is we said that I was going to stand back a little bit and get involved in more business and concentrate on that," Evernham said. "I handed the competition off a little bit, and we basically got off of our philosophy. We didn't implement our checks and balances as we had been."