This will serve me nicely

Fuel Conversion Chart
Energy Conversion Factors

1 Cubic Foot of Natural Gas = 1,030 Btu's

1 CCF = 100 Cu Ft = 1 Therm = 103,400 Btu's

1 MCF = 1,000 Cu Ft = 10 Therms = 1,034,000 Btu's = 1.034 MMBtu's

1 Gal Propane = 91,600 Btu's
1 Cu Ft Propane = 2,500 Btu's

1 Gal Gasoline (mid grade) = 120,000 Btu's
1 Gal of #2 Fuel Oil = 139,000 Btu's
1 Gal of #4 Fuel Oil = 145,000 Btu's
1 Gal of #6 Fuel Oil = 150,000 Btu's

1 Barrel of Oil = 42 Gallons

1 KW = 3,413 Btu/hr

One question that comes in mind is: are propane-driven vehicles really more cost-effective than gas-driven ones?