Is my 340 Overcarbed? Avg 5-6 MPG

Do you see in the picture of metering block with power valve removed the two holes behind power
valve? Those are power valve channel restrictions(pvcr). I can see how small they are. Think of those
as jets, because that's exactly what they are. When your power valve opens, those "jets" combined
with your main jets create your w.o.t. a/f ratio.