NASCAR officials announced a tweak in the 2019 baseline rules package for select tracks, adding aero ducts to the three remaining race tracks where a 550 horsepower engine will run, but where cars were not originally required to be fitted with the ducts — Pocono Raceway, Darlington Raceway and the season finale at Homestead-Miami Speedway.

Previously at those three tracks and Atlanta Motor Speedway, NASCAR required teams to use brake ducts or block-offs in that area to help cool the brakes.

Following the racing at Atlanta earlier this season, concerns about air flow to the brakes were alleviated, according to NASCAR.

“When we originally looked at which elements of the package to race at each track, we wanted to err on the side of caution at a few tracks where there may be some brake cooling concerns,” said John Probst, NASCAR senior vice president, innovation and racing development. “After reviewing data from Atlanta, and with what we’ve learned over the first 11 races, we believe we can use the ducts without issue. In conversations with the teams, they emphasized the desire to focus on one race package, which will continue to improve the racing.”

Created to bolster competition with enhanced aerodynamic and engine configurations, the 2019 rules packages are tailored to the specific tracks on the Monster Energy Series circuit. A smaller tapered spacer to reduce engine horsepower to a target goal of 550 and aero ducts to foster tighter racing were implemented on a majority of speedways measuring longer than one mile.

The rules packages for the remaining tracks on the schedule have not changed.

For more information, visit the NASCAR website.