What mileage does your slant six powered ride get?

No O/D not mine, documented from 1964. If you read the article, it describes conditions, and that these were off the lot cars with strict fueling and non tampering policy. LOL that you guys can't believe some of the stuff that some of our members have achieved. Mine by efficiency as I was building for power, not fuel economy.
I was building for fuel economy, and my engine is not stock. So I don't understand why some don't believe that I can get upper 20's MPG