The cars of Kyle Busch, Denny Hamlin and Christopher Bell will go to the back of the field for the start of the Pennzoil 400 at Las Vegas Motor Speedway.
NASCAR issued L1-level penalties after the cars did not meet pre-race specifications.
The penalties also come with 10-point deductions in team owner and driver standings.
Busch had been scheduled to start at the front of the field after rain forced qualifying to be canceled.
On Friday Busch, Hamlin, Bell and the other Toytota’s of Martin Truex Jr. and Erik Jones were docked practice time for attempting to change the shape of the front fenders with body filler.