In 1935 a Canadian named Charles Nelson Pogue built the first of his 200 miles per gallon carburetors. Well that is what he claimed you could get with his carburetor. By the end of the 1930s, he had built and sold 317 of the carburetor he called the “Winnipeg” carburetor. The carburetor did existed in reality, but the 200-MPG was pure myth. There were two serious problems with the design. The first one is that the claim violated the First Law of Thermodynamics. Second, the best mileage achieved using a Pogo 200-MPG carburetor was 35 MPG when the carburetor was installed on a Ford Mustang. The Mustang suffered a dramatic loss of power in the process and was all but impossible to drive. As far as anyone knows no one has been able to get anywhere near the mileage Pogue claims.
The one thing that jumped out at me was when the book's author claimed that an automobile running at highway speeds ran at an air/fuel ratio of 49:1 based on engine displacement, RPM, and fuel usage. He made one significant error: he forgot (or neglected) volumetric efficiency, or V.E.
Just because an engine displaces 300 CI (or 302, 351, 460, 255, 221, or any other number you wish to use) does not mean it will actually draw in and exhaust that much air over the course of two revolutions. V.E. typically is maximum at peak torque, but only when the throttle is wide open. Note I did not say, "V.E. typically is 100% at peak torque"; there are constraints in practical engines that prevent that, such as intake and exhaust manifolds, carburetors, air cleaners, and exhaust systems. And there is an unavoidable constraint at part-throttle operation, namely, the partially closed throttle itself.
Based on this fact, many if not most of the book's conclusions are flawed.
I talked to a guy not too long ago whos friend had a Thunderbird with a supposed 200mpg carb. You all know the story of how it did great then it got replaced and then Ford showed up and offered him a new car every 5 years or so.
I didn't believe it until he should me an in depth picture that was dated in the '60s. I was still skeptical though.