Gas Mileage query Holley 318

At 2k-2400 rpm you are still running on the idle circuit and haven't fully transitioned to the primary jets. Pin the IFR size and see what size they are. Reduce the IFR in .001 increments until it stumbles, then go back up .001. If the carb is 4 corner idle do both metering blocks. Vacuum advance is also important if you want gas mileage.