Is my 340 Overcarbed? Avg 5-6 MPG

". A/f is steady at 12.4 at cruise. I agree carb needs to be retuned. It was replaced from the original 770 due to internal leakage and was not the same tuned carb that was on that Dyno run.."

yep, I thought you were running fat but the old A/F table threw me. Cruise can be up to 17 as you require little of the motors peak power to maintain speed. Easier said than done on a carb, a few mouse clicks on an EFI.