CONCORD, N.C. — NASCAR on Wednesday levied a heavy fine against Kevin Harvick, one of the most outspoken drivers about safety concerns on the Next Gen car, for alleged modifications found on his Ford at Talladega Superspeedway.

NASCAR docked both Harvick and Stewart-Haas Racing 100 points each, fined crew chief Rodney Childers $100,000 and suspended Childers for the next four races. NASCAR said the penalties were for “modification of a single source supplied part.”

“Seems strange…” Harvick tweeted minutes before the penalty was announced.

NASCAR has a reputation for making things difficult for teams that for various reasons the sanctioning body finds out of line. Harvick’s rants last week about the safety of the Next Gen car may have been why the No. 4 Ford was selected to be taken from Talladega to its North Carolina R&D Center for a deeper inspection.

NASCAR maintains that the selection of cars for postrace inspection at the R&D Center is done randomly. Competitors believe there’s nothing random about the process.

The Next Gen has been under increased scrutiny the since the playoffs began in September with four consecutive races in which the car had issues. From car fires (Harvick’s caught fire in the playoff opener), parts failures and tire failures, the Next Gen struggled to hold up in playoff competition.

But the bigger issue was the stiffness in the rear of the car, which has contributed to concussions for both Alex Bowman and Kurt Busch. Bowman is out for a second consecutive week and Busch will miss his 12th straight race on Sunday at Charlotte Motor Speedway.

NASCAR on Wednesday was scheduled to crash-test computer models of changes that potentially can be made to the rear of the car to help redistribute the energy away from the driver during a crash. But any solutions won’t be implemented until next season. There are five races remaining this season.

With the suspension, Childers would likely be permitted to work only the season finale. Harvick was eliminated in the first round in the playoffs — largely because of problems with his Next Gen car.