Our lightweight aluminum gas tanks are designed to fit between the frame rail and rearward of the axle on 1963-66 Chevy and GMC trucks. By moving the fuel tank out of the cab, you gain much needed room to allow for further customization, also increases fuel capacity and safety. Made of heavy gauge aluminum, these gas tanks offer a light weight design and are fully baffled.Vent bung size is 1/4″NPT. Fuel feed bung size is 3/8″NPT. Available in side or bed fill, add $40.70for side fill.