This is the statement I included in my airworthiness package. I0 390 Exp 210 hp.
The L/H tank was filled with 5 gallons of 100LL and the fuel line was disconnected at the Fuel Servo inlet. The electric fuel pump was run briefly to verify flow. The nose of the aircraft was then elevated to the maximum take off angle plus 5 degrees, which equaled approximately 17 degrees. The pump was then run continuously for 1 minute with the fuel collected in a gas can with a known weight. The collection tank was weighed and the net weight was 3.45 lbs. This was in turn correlated to gallons per hour, which equaled 34.4 GPH. Fuel consumption of the IO-390 at full rated power is approximately 17.5 GPH. The available flow is approximated twice the amount required for a max power take-off at sea level.
Test done by builder and witnessed by xxxxxx, DAR.