You can change the jet AND metering rod sizes so that under WOT the A/F will be ideal for max power (~12.5:1) and under part-throttle cruising the A/F will be leaner for max fuel economy (~15.5:1).
Maybe I'm opening a can-O-worms beyond the scope of a web discussion, but is there an economical way to get those ratios & diagnostics? Or maybe the better question is: How do you 'plug-in' to say, software to actually give readings? Is it as simple as tapping a sensor into the carb, or manifolds?
I imagine that to get into that kind of tuning, one has to get pretty serious about carb tuning (& maybe do it for a living).
