[sokoloff]

Or placed an inflated basketball in the fuel tank when it was going to be measured for capacity, only to deflate the basketball for the race.

Or load the car with cold (more dense) fuel.

Or (allegedly) race a 15/16ths scale car with a matching 15/16ths scale street car strategically parked in the track parking lot so the scrutineers could compare against a stock car and see that it matched.

Or built a race engine with the correct size cylinder in the easiest to measure location and oversized cylinders in every other position.

Other racers had special lead-filled radios and overweight helmets that would be in the car for tech, then get changed out before qualifying. Or lead shot filled in the frame rails and a wax seal or threaded fitting to keep it in. Darrell Waltrip tells a hilarious story where the threaded seal was in the jack point and NASCAR jacked the car to go look for it. Moving bars of Mallory (tungsten, basically) from the right to left after passing tech. Another racer was caught with a 22 gallon tank (20 was the limit at the time), apologized and agreed to change it. (He changed it to a 28 gallon tank.)

[Infernal]

> Or load the car with cold (more dense) fuel.

This is why F1 specifies fuel capacities and flow rates in kilograms.