LOL that's cool. I do the same thing myself. I got a plan sheet for making those 150 mpg carb's laying around here and I haven't turned it up yet.
Back in the 80's there was this group who went from town to town giving talks with hand out info for like $200 bucks a seat. Some friends of my Dad all ponyed up $10 each to send the chief mechanic to the seminar to learn it and come back and teach them how. They took the plan sheet and xeroxed each guy a copy. I got a knock off of the whole thing later. They had those guys on TV talking to a newsman showing him under the hood of this big white Cadillac.
When the shop's chief mechanic got back he mentioned something they weren't talking about under the hood. It was a water vapor injector. He got the guys off by themselves and asked them about it and they "ahem a yeah ahh" well that's to smooth out it's running. (appearantly to cool down the combustion temps and eliminate the explosive pre-det from the ultra lean fuel mixture)
So I'm still hunting for that envelope myself.
The chief mechanic actually thought it was dangerous as they ran the fuel line thru the upper and lower tanks of the radiator like a domestic heating coil to preheat the fuel. The fuel then went into a felt lined air cleaner with an extended upper air cleaner cover stud. When the cover was installed there was a spring under a wing nut so if a backfire occured the lid could rise to allow a burp and then snap back to keep a fire from occuring. The bottom of the air cleaner had a 3/8 inch copper tube soldered to it to run coolant thru to help heat the fuel to a vapor. Can you imagine ?
Basically you heated the gasoline to a vapor opposed to an automized spary into the carb. (this is where the "KeroSun" heaters get their tremendous efficiency...they burn the vaporized Kero which comes up thru the cotton wick into the glass fiber final wick which can take the high temps. Thus what burns is Kero vapor) And that's what their principle was with the gasoline.....but I figured it would run so lean they wouldn't be able to keep valves in the Cadillac unless they had had stellite or sodium exhaust valves installed in the heads. (and again not told anyone....like using the water injector)
But that's the experience I had with the 150 mpg Carb. I figure a 460 V8 with water injection rigged with a electric engine heater (like for cold mornings) and starting and running it normally till it reached op/temp would get it up to speed to switch to the low flow regulated fuel supply.
To me if I had to live somewhere like Colorado and drive a couple hundred miles at a stint....it would make sense. But before I did such a mod I'd want to pull the heads and install some righteous exhaust valves in them.