I doubt this one was used traditionally, but it's got a nice old style. It's from a late 50's to early 70's Rolls Royce/Bentley and originally sits behind the license plate.
Like @Just Gary said , 50s or many times It was common to see a rag stuffed in, Or if you want Some Vintage Art Deco "Bling "
There was an old hot rodder in Melbourne who had a Vegemite lid as a fuel cap, just to stir people up, it was a nice 34 coupe, 60's style highboy
BrandonB, that cap with the slot looks like the water fill cap on a Tartan 37 sailboat (I crewed on one) John
It's hunting for us (which I LOVE) but back then there wasn't much of that consideration since everything was part of the aesthetic. There was a lot less soul-less crap produced. Now we hunt and become historians of minutia. We know more details about hose clamps and gas caps then ANYONE ever did back then... not even the local parts counter guy. They had caps over there on a peg and hose clamps over yonder or somebody hopped a fence and nicked one off of a field car to save $.25. Way more stuff was interchangeable and there was so much it! Vehicles left for dead out in the back 40 or waiting for resurrection behind someone's garage or forgotten in alleyway behind a row of suburban homes. Many hot rodders' stories I had heard all has some element of taking parts from vehicles in such situations. There were a few other about hopping fences and loading pockets for nuts and bolts to get a front clip bolted on or pulling a transmission from a cow pasture and stepping in endless cow patties and falling over while trying to remain out of earshot so they could get their hot rod together. Only many years later when asking about tiny, "insignificant" details would these stories be told.
I have a simple chrome flip cap in a box somewhere. I will dig it out. If you like it, you can have it.
I've got one of those Jaguar hinged, springloaded assemblies with key etc, I think the Jags had one on each side of the car, they're pretty trick, chrome is vg, send you photo's if you're interested.
For me the coolest cap are the old Moon Equipment spinners. Couldn’t find one that wasn’t a fortune so I made one that kind of resembles it.
Some MGs models in 70s years had a simple flip top cap , about 2 to 2-1/2 Inch round , on back side ,had a slide on neck ,for hose , its been so long ago , I paid like $2 in 90' Now probably $100 ? Some boats, small same with flip cap Mounted directly to tank
Called a deck fill... check westmarine, bass proshop, and check amazon too.. they make some where you can press down to pop open / remove the cap instead of using a deck key...
Roadster Supply sells a solution like that. https://www.roadstersupply.com/1932-Ford-Gas-Cap-Screw-On-p/rsc-62510.htm I put one on the Vintique tank in my 5W. Very nice piece.
Agreed, nice and simple but in a jurisdiction like mine where they actually do a safety inspection before giving you a plate, this will not pass, ever.
I started a thread on "kind of" this subjekt a few years ago. It did not generate alot of responses but here is the link. https://www.jalopyjournal.com/forum/threads/gascap-question.955807/
I have the perfect one for you. Trying to get my camera to load pics. Having problems at the moment. Send me your phone number and I'll text it to you. I guarantee you will like it. I have fairly good taste in hotrod parts. It will require a small amount of work to adapt it but will be period perfect for your gowjob. Dale
What an idea, thank you Phil! I just have received the geniune one I found on eBay and it is perfect: need no modification or painting to be fitted on my "Bitza" project