Is my 340 Overcarbed? Avg 5-6 MPG

Yes there is only 162 miles on the complete drivetrain since the rebuild. As you can see in that picture I only had 26 miles on thetrip meter and I was down to half a tank. It is a reproduction tank and sending unit. When I filled up tonight the tank took 12 gallons. Speedo is dead on because I used a GPS app on my phone and the speed matched.