I have never had a low light or check gauge light come on either, and my wife has run it damn close to empty. Like drifting into the gas station empty.

 

my bro's 01 ss check gauges light comes on when there is 2 gallons of gas left

 

recently I had to replace my fuel sending unit through warranty b/c I would always see how many miles I get on a full tank. I no longer let it get below 1/4.. My fuel gauge would act up bouncing up & down when it showed below 1/4 so I just had my warrant fix the problem. My tank when I would fill up showed a lil over 13 gallons.. I guess I have a 13 gal. tank