Biffle's Bristol car within regulations

Biffle's car was impounded by NASCAR following the race at Bristol, in which he finished fifth, as it was said to be too low in the rear. Eight different cars were checked for height measurements following the race.

However, NASCAR Nextel Cup director John Darby clarified that the NASCAR rule book for the new car does not have a specific limit on the height of the rear of the car for every track.

"In regards to post-race height, [the rulebook] basically said that the maximum height of the car as it applies to the downforce tracks, there's a dimension given," Darby stated.

"The only two tracks currently that there is actually a minimum height prescribed in the rulebook is Daytona and Talladega.

"We understand we have to have a minimum going down the road to protect the overall height of the entire car, but where we're at right now is not knowing where the teams need it, not knowing where we need it."

Darby also stated that the No. 16 Roush Racing car was simply out of the minimum height window officials expected all cars to be by the end of the race, as they work on setting a limit for it.

"The 16 car was out of our preliminary range we were looking for to try to see if it was reasonable and workable. The winner of the race, for example, was probably a breadth away of being in the same position the 16 car was," Darby said.

"There will be a rule someday once we understand what the teams need as a working range, no different than the period of time that we took to establish what was too high because ultimately the teams have got to have enough room to move to be able to race the cars."