From a Google Lens search: This is a vintage "Goodwise Lock" locking gas cap, model #400. It is a chrome-plated, military-style cap often used on classic vehicles like 1946-71 Chevy/GMC trucks and Jeeps.
I think it would be worth getting a key made for it and keeping it on the truck.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
