Two weights to consider. Race weight is always with the driver. A class that has a weight minimum will weigh the car on the return after the race. The driver stays in the car. If you are too light… you loose. An example is the heavyweight classes that require a minimum of 4200 lbs. That way a heavy driver is not at a disadvantage racing a lightweight. The other weight is legal chassis weight. If you check the NHRA Cert tag on a roll cage, it will have a max weight limit. To pass tech, the car has to weigh less then the cert weight limit on that tag. That will be the weight of the car without driver.