Need recommendation for a Carb for better MPG!

Over the years carburetor wise the biggest difference in mileage i ever saw was when I stupidly wanted to try a Holley 1850. Because my brothers ramcharger had one and it seemed to run good. Both his and mine (Holley carbs) wound up in the scrap pile in short order, because we couldn't pass a gas station. At the time I had a 318 powered Cordoba. Went from those to TQs that I randomly picked at the junkyard and both ran just as good as those Holley's did but mileage on each dang near doubled vs what they were getting with the Holley 1850s....
In my brothers case he lived a couple of towns over and had to go for smog test. Couldn't get his ramcharger to pass to save my life. Went to that TQ and passed with flying colors.
So that's what made me go find another TQ for my car. (And I've never had to succumb to or bow down to a smog test, on any vehicles I have ever owned with where I live. I've since moved 30 miles further south of where I was at in those days)