Pougue carbs and Fish carbs are different animals. The early ones (fish carbs) were designed for smaller engines, since he was designing for economy.So, they were sized for flathead and inline/slant 6's, smaller ones like the 223. Then, people wanted them for V-8's, so he made a 2 barrel model. They are REALLY rare, because it was soon after that that the Postal Inspectors moved in, and arrested him for mail fraud.In the 80's, someone (his son, I think) ressurected the product, for a while. They improved the basic design in all sorts of ways, including sizing it bigger.Since it is a type of Constant Velocity carb, you really can't overcarb.On the otherhand, the drawback to the predator, (another Constant velocity carb) is that the makers were totally focused on performance, and so its BIG. Its 'rated' 300-900CFM, and theres another, Kendig i think its called, goes to 1100 or 1200 cfm.To each there own, and its fine for you to say "Prove it with independent testing before I'll buy", its your $ after all.Such testing and documentation costs a lot of bucks, and its not always easy to verify the independance. A lot of health food/alternative medicines quote some study, usually conducted outside the US, and impossible to verify.As for the 3rd rule of thermodynamics, I always think about stomach ulcers.For 50 years or more, it was established medical knowledge that ulcers are caused by stress.There was this Dr. that went to work in Africa for awhile, living with the people he was caring for, a tribe with a simple lifestyle.Some of them had stomach ulcers. Observing there lifestyle, it seemed to be fairly unstressful.(They didn't own watches, or know how to tell time with one, for example.) And he saw that some who didn't have ulcers seemed to have more stress than some of those who did.So, he rejected 'conventional wisdom', and tested both those with and without ulcers. He found those with invariably had H.Pylori bacteria in their stomachs, and those without never did. He treated them with an anti-biotic,and they were cured of their ulcers. When he returned to the U.S., he documented his research, and went around to AMA meetings to make a presentation of his findings.Invaribly within the first 2 minutes, people were leaving, and shouting him down with derisive comments.Fortunately, he published his findings and they were eventually accepted.I'm more experianced with medical science than with engineering science, and medical science is full of similar stories. I'm sure engineering is, too."If God had meant for man to fly, he'd have given him wings." So, I don't know if 100 mpg AND decent performance in real life driving conditions is possible. I do believe that ICE's are fairly inneficient, and if the efficiency could be improved the mileage would go up.Oh, and over 100 mpg in a car has been achieved, with lots of testing and independeant documentation.In the 50's or 60's, I believe it was, they had a mileage contest. An aquaintance recently bought 1 of the cars, that was entered by Shell oil.It got something like 140 m.p.g. Its a fiat, although other entrants used Opels.The track was a flat oval, so no grades, and the maximum required speed was something like 14 mph.The air intake is fully insulated, and heated by the exhaust.I'm sure theres lots of other tricks, but thats whats immediately obvious.Anyway, thats why I qualified about reasonable performance.Jim