MA8174 - What is the outside diameter of the 1967-71 Dodge/Plymouth A-Body Fuel Cap-Chrome and the outside diameter of where the cap fits within the fuel filler neck?

Product description: 1967-71 Dodge/Plymouth A-Body Fuel Cap-Chrome

The outside diameter of the top of the fuel cap is 3 and 1/4 inches. The outside diameter of the ring on the underside of the cap that fits within the fuel filler neck is 1 and 3/8 inches. Please see the two photos below for clarification.