The small primary throttle theory is an engineer's pipe dream . In all cases,adding a second carb on a Chevy 6 gave better fuel mileage if driven normally.This is well known by those who actually worked on these engines.We are takin old Chevy 6's here.
Several years ago wrote an article for Inliners on the various carbs I had tested out on a 261 engine,Holly 350 and 500 2bbls,old Carter WCFB and small AFB's and the butt ugly Pinto carbs, and even 2 Rochester B's.
In all cases,one the carbs were jetted properly,fuel mileage was all about the same,of course there was performance differences.
For better fuel mileage,work on the areodynamics.
