I read all the old post before I wrote this. I'm looking for a pop-up style gas cap like ones used on some 6o's Mustangs that also fit my 73 Maverick. My impression from reading old post is that some do fit without modification but the diameter may not have the visual appeal I'm looking for. Aside from Mustang does anyone know of anything that has a slightly smaller diameter that fits without to much modification? I looked around for aftermarket custom caps for Mavericks but couldn't find anything.
Did you come across this one in your research? http://mmb.maverick.to/media/flip-up-71-73-mustang-gas-cap.17149/
I have an old Eelco Mustang cap from the late '60's. The cap is smaller in diameter than the stock Ford caps. I can get a better pic tomorrow if you want.
Since it's meant for an early Mustang the mounting holes are in the same locations as the filler pipe holes, it just bolts right up. The cap is 4" in diameter, the hinge and latch go little beyond that. They're tough to find because they haven't been made since the late 60's. Every once in a while one comes up on eBay. For 2 summers, until I found the Eelco cap, I ran a flip cap from a Charger. It's pretty much the same size. I have that on Craigslist now. https://york.craigslist.org/pts/d/york-charger-barracuda-gtx-flip-open/7048061434.html
An Eelcco cap is what I've had on the car since 1973. A couple years ago I took it to a powder coater to get it powder coat chromed because it had gotten pitted and ugly looking. He put it in an 800 degree cleaning oven. Zinc die cast melts at around 700 degrees. It came out looking like a grey lump of $h!t. I was beyond pissed. I ran the Charger cap for a year and a half until I came across this NOS Eelco on evilbay. Screws and gasket were still in the sealed bag after 45+ years!