I had a couple of the 100 mpg carburators from the early 80's that I bought from a garage sale. They were all aluminum custom cast units. Very simple inside and out. I believe they work like the high preformance "Preditor" carburators you can still buy. The throttle blade was just a blade with no linkage at all hooked to it. The heart of the unit was the big vacumn diaphram that pulled the top plate open. The diaphram was hooked to ported vacumn that heald it shut. Once you open the throttle, the vacumn would drop and a spring would override the vacumn. Only adjustment was the idle speed and idle mixture.
I had it on my 318 Dodge for a week or so. It would get about 1 to 2 better mpg but the loss of power wasn't worth the trouble. Plus it was very slow to get going, then it would take off, so it was hard to drive. I had all the papers and engineering work sheets. I finally scraped them for the aluminum.
Joe
