It has never been installed. Outside diameter is 3-1/4 inches. The item "1974 Dodge Sweptline Pickup Truck Locking Gas Cap (EXC CAB TANK) D-100 D-200" is in sale since Friday, June 29, 2018. This item is in the category "eBay Motors\Parts & Accessories\Vintage Car & Truck Parts\Air Intake & Fuel Delivery". The seller is "tillyfour" and is located in Rockford, Illinois.This item can be shipped worldwide.