I had a customer in New Smyrna Beach who rebuilt carburetors. Imagine six cobbled together rooms added to an old house, then, add every carburetor you have ever seen, imagined, or had a bad dream about by piling them to the ceiling on shelves, the floor, other carburetors, tool boxes, and lying on the ground out back. I shit you not that we're talking a "Hoarder level" of carbs stuffed into the building to the point that there are trails through the piles of them in every room. Walking around in there on the narrow paths is an exercise in avoiding tetanus, but somehow, they all know where anything is, all you have to do is ask and they start digging.
But the old dude that owns it, if you ask him about any car ever made, he can immediately name the make and model of the carb required for that car.
I told him I had a Mighty Mite and he said, "Can't find the correct rebuild kit, can you?"
He explained that the jeep had a one off Holley 1925 and if I wanted it rebuilt properly, just to let him handle it. If I didn't care about complete authenticity--and we're talking about a vehicle that I know of only 5 people who would even know that the carb isn't exactly "right"--he would just sell me a brand new Brazilian one. It worked perfectly and didn't matter at all that it wasn't the correct version of the 1925.
A few years later, I took the Mite to Jeeptoberfest in Ocala and went to start it on the trailer and got nothing. It could crank and crank and crank, but wouldn't fire. A buddy who'd brought his started helping me with it and we discovered that the fuel pump was fucked.
I called every place within a hundred miles to see if they had one. Not only did they not have it, they'd never heard of it.
Defeated, we pushed it back onto the trailer and I took it home. The next time I stopped in New Smyrna Beach, I walked in and handed it to him. He rattled off exactly what model of AC pump it was and then said, "I fix carbs. I don't screw with fuel pumps."
Had to send it to a guy in Massachusetts, who I imagine has the fuel pump version of the carb hoarder's shop.
I'll bet there's a third guy, probably around Chicago, who has a building stuffed to the rafters with British fuel fittings.