Sorry for reviving a old post but this was not mentioned ...There was nothing mentioned in the post about this Real life issue that can happen with drag cars.
So if you are running low on fuel but you you choose to race. Your car can start Spluttering, Pinging, Hesitation,Backing fire from low fuel pressure fuel starvation, car starts running lean etc... (This Normally eats up spark plugs)
So if you decide to Race with a low tank of gas your car in theory is lighter but if the stretch of road is too long you do so at your own peril