Convert from erg to gallon [U.S.] of automotive gasoline

Unit Definition (erg)
The erg is the unit of work or energy in the CGS system, equal to the work done by a force of one dyne acting through a distance of one centimeter. Equivalently, one erg is the kinetic energy of a mass of 2 grams moving at a velocity of 1 cm/sec. This is equal to 0.1 microjoule, or about 7.375 x 10E-8 foot-pound. The name of the unit is from the Greek word ergon, work. There is no symbol; the word is spelled out in full. Adding prefixes is a problem: 1000 ergs is usually called a kiloerg, but one million ergs is a megalerg, the "l" being added to ease pronunciation.

Unit Definition (gallon [U.S.] of automotive gasoline)
U.S. liquid gallon is legally defined as 231 cubic inches, and is equal to (exactly) 3.785411784 litres (1 L = 10-3 m3) or about 0.13368 cubic feet. This is the most common definition of a gallon in the United States. The U.S. fluid ounce is defined as 1/128 of a U.S. gallon.