National Motorsports Appeals Panelist Bryan Moss heard Chastain's appeal and chose to uphold the original penalties assessed by NASCAR for the No. 44 being too low. Niece Motorsports owner Al Niece had said the truck passed opening and pre-race inspections and may have suffered minor damage during the race that left it too low.
Chastain's disqualification was the first under strict new rules put in place this season to deter cheating and it was the first time this year a winning car had been DQ'd on race day.
NASCAR said the last time it disqualified an apparent race winner was April 17, 1960, when Emanuel Zervakis' victory at Wilson Speedway in North Carolina was thrown out because of an oversized fuel tank. The last driver stripped of a victory was Mike Skinner the day after a 1999 race at Atlanta Motor Speedway for an unapproved cylinder head.
Chastain's misfortune gave the victory to Brett Moffitt and Chastain will be scored as if he finished last in addition to his victory and bonus points being stripped away. Chastain, who led the final 141 laps, also lost the $50,000 he had won for taking first in the "Triple Truck Challenge" marketing promotion that included the Iowa race.
"I'm not backing down from the fact that we beat everybody," Chastain said in a Sirius radio interview Monday.
The loss could be devastating to Chastain's playoff hopes.
Chastain recently decided to switch his championship pursuit this season from the Xfinity Series to trucks, but he was not allowed to count a trucks win at Kansas because he was not racing for the series title at the time. Drivers who have won races only need to finish 20th or better in the regular season to make the postseason, but Chastain now has a long way to climb.
NASCAR announced in February that thorough post-race inspections would take place at the track instead of midweek at the sanctioning body's research and development center outside of Charlotte, North Carolina.
Winning teams found in violation of the rules in previous seasons were penalized with post-race fines, point deductions and/or suspensions. But drivers didn't have victories taken away from them until Chastain was stripped of the victory.
Chastain said in the radio interview he let NASCAR's decision Sunday bother him for "about an hour" before he shifted his focus to this weekend's races at Sonoma Raceway.
"I'm not letting this get us down because we have such a good program here at Niece Motorsports," Chastain said.