With a 22-Gallon Fuel Tank Conversion Kit, your Mustang will benefit from six extra gallons of fuel, which is almost 40 percent more! If you are running a 4-barrel carburetor or any other type of performance modifications, looking for increased fuel range and security, or just simply tired of filling up your tank so much, this 22-Gallon Fuel Tank Conversion Kit is perfect for your 1967 or 1968 Mustang!