Pruett and Ambrose top practice

Pruett set the fastest time of the day in the first practice session with a lap of 1 minute 42.493 seconds at the wheel of the No. 40 Chip Ganassi Racing Dodge. He was more then three tenths clear of his closest rival, Australian Marcos Ambrose.

"This is the most difficult track on brakes, without a doubt," said Pruett. "It's very technical, it's very high-speed, the turns are very slow so you're getting to pushing 170 mph then you're getting back down to 40 mph for some of the turns and that really takes its toll on the brakes."

"It's got a real rhythm to it and quite frankly it's all lined with cement walls. Any sort of mistake is very costly."

Locals Patrick Carpentier and Jacques Villeneuve were fourth and fifth fastest respectively behind veteran Boris Said, although both were more than a second off from Pruett's pace.

The final practice session saw Ambrose take over the top spot, although he didn't improve Pruett's morning-session time with a lap of 1 minute 43.165 seconds. Italian Max Papis followed more than two tenths adrift, while Pruett was third running three tenths slower than the Australian after setting pole position for the Grand-Am support event.

Patrick Carpentier, who was on pole position for last year's race, was once again the fastest local in fourth in the No. 9 Gillett Evernham Dodge, while his compatriot Villeneuve was sixth in his Braun Racing Toyota, once again more than one second off the pace.

There is a fifty percent chance of rain for Saturday and the possibility of racing under those conditions has been discussed. Goodyear has an allocation of wet weather tyres in case they are forced to run the event on a wet track.

Ambrose wouldn't mind having a go under those unique circumstances for a NASCAR race.

"Depends on if NASCAR wants to run in the rain," Ambrose said. "Yeah, bring it on. We'll run rain or shine. I really feel like the race is going to be long tomorrow. There's going to be a lot of cautions. The weather is going to be unpredictable. It's going to create a lot of change in the outcome of the race, I'm sure."

Just as it happened in June in the Canadian Grand Prix, the track has been breaking up on the hairpin. However the problems seems to be for now much more under control relative to the Formula One race weekend.

Saturday's qualifying will be split in nine groups of four or five cars with the fastest from practice going out last. While Villeneuve will be on the penultimate group, Ambrose, Papis, Pruett and Carpentier will make up the final group of qualifiers.