First convert 14 gallons to grams (52,995.76g), all chemical reactions are related to molecular weights, in this case, 112 atomic weight units for gasoline, 32 for oxygen, 44 for carbon dioxide, and 18 for every mole of octane, 8 moles of CO2 are produced. The proportion will be (52,995.76g x 8 x 44 atomic weight units) / 112 atomic weight units. This equates to 166558.103g. Next, we convert grams to pounds. 367.19776172602 pounds.