JOLIET, Ill. - As long as he sits still inside the car, Tony Stewart said, he doesn't feel any pain. However, that might be difficult to do for 267 laps during today's USG Sheetrock 400 at the Chicagoland Speedway.

Stewart said he was still sore after crashing Friday during practice. He drove three laps during practice Saturday after gaining medical clearance to compete and will start his Home Depot Chevrolet in today's main event (3:30 p.m., NBC).

"It's a little more painful when I get going," Stewart said. "But it's going to be that way. To have a hit like we had (Friday) and ... not to be sore is virtually impossible.

"I still don't remember what happened, but the good thing is I don't feel terrible. I'm just real sore. I feel like I got invited to a baseball bat war and didn't get my own bat. Everything on my right side feels real good; everything on the left side is sore."

J.J. Yeley qualified the car Friday while Stewart was being treated at a hospital. Because the team changed cars and drivers, it will be forced to start last today.

The only other time Stewart has had to start last after changing cars was a year ago at Chicagoland. He used a backup and won the race.

"I'll be honest, I have no concerns about it," he said of starting last. "We're going to have to work hard (today). The good thing is the team has a lot of momentum. I don't care how sore I am (today). I'm going to tape my elbows up and keep digging all day."

The crash on Friday came as Stewart was driving through the fourth turn. He apparently cut a right front tire and hit the wall.

"I don't know what happened, other than just what I saw on tape," he said. "One of our photographer buddies down on that end said he heard a bang and saw a puff of smoke. So evidently a tire went and we just went straight in the fence and wrecked from there."

HAPPY HOUR: Kyle Busch posted the fastest lap in the final practice session for today's race.

Busch's Chevrolet was clocked at 182.371 mph Saturday. Unlike most other races, Chicagoland does not use the impound rule, meaning teams qualify Friday and have two practice sessions Saturday. That allows them to make radical changes to the car after time trials. Since cars are changed to withstand longer runs, speeds are dramatically slower than qualifying. In fact, Busch's best lap was nearly 6 mph slower than the best speed in qualifying.

Mark Martin was second- fastest at 181.726 mph, followed by Ryan Newman in third at 181.641 and Robby Gordon in fourth at 181.464.

Pole winner Jimmie Johnson was 18th-fastest at 180.132.

STACKER 2 GONE: Kenny Wallace's Busch Series team spent hours making a significant change Saturday to its Ford before the USG Durock 300 for the Busch Series.

They pealed away the sponsor decals from Stacker 2 and replaced them with Kraft and Oscar Meyer.

The sponsor, which has been with Wallace for four years, is preparing to battle several lawsuits concerning the herbal stimulant ephedra.

"The whole pharmaceutical industry is having their problems," Wallace said. "They just can't be in the sport any longer.