Perhaps your fuel line leak is larger than you think and contributing to the poor mileage. Also, you say you are using non ethanol gas at 93%. If you mean 93 octane, I don't think that is necessarily good. These engines are low compression and may not burn that fuel very well. I don't know whether that would contribute to poor gas mileage but at least it is a waste of $$. Could you clarify what you meant by the type of gas?
For comparison, I get 12 mpg with my unloaded '50 COE with a later 1958 235, up and down mountain roads.
Kent


1937 Chevy 1/2 ton
1942 Chevy 1/2 ton
1947 Diamond T Model 509
1951 Chevy 1/2 ton
1950 Chevy COE Model 5700 ~ "Barney" ~ And more pix