Poor gas mpg

I thought to mention beside the rear end gears, to think about what your CARTER AFB metering rods size is! Owners that are second or third owners of their car need to wonder if the carb ever was rebuilt and if so were the right metering rods reinstalled in THAT carb. You need to understand that two brass metering rods are lifted out of the fuel jet HOLES as you step on the gas and has to be correct for performance. The jet holes that the metering rods go through are stander size for that carb, but the rod thickness depend on engine size and HP. Think of it this way , if the jet hole is always the same size .A thinner rod increases fuel flow 1. ( to much -fouling plugs,dark smoke car can feel like it lugging and can Diesel do to carbon build up) .To thick a rod ( plugs run hot, engine runing hotter,no power, pinging, stuttering) I found my 57 doing the second. like the three bears you need to try different ones to get it just RIGHT.Early Corvettes have Carter's and the same condition to deal with.