From what i vaugly know about variable venturi carberators. it seems like they would work good, in theory at least. could anyone explain to me what made them flop?

 

They were very tempermantal. I guess it was hard to keep the upper flaps in synch with the actual air demand. My Dad had a 1980 Crown Vic that had one on a 351W. Had a police machanic work on it that worked on them all of the time. It never ran right. I eventually installed a Holley direct replacement for it. Never had anymore problem and got much better mileage to boot.