LOL yeh no kiddin tam, you bastard!
Yeh muzzy, gasoline does weigh a lot. It's actually 6.7 pounds / gallon, so a 1/2 tank in my car is roughly 50 pounds. I try to run it 1/4 to 1/8 tank if I know that I'll be racing, other then that, I try to never really fill above 3/4.