Got back from the Old 27 Tour. Logged approx. 700 miles in 4 days in my 1960 Buick LeSabre Convertible w/401 4BBL Nailhead engine. Used not a drop of oil, Trans fluid still clear red & up to full level, engine ran smooth and cool as a cucumber and also checked gas mileage. Gas mileage ran from 17 to almost 22 (21.8) MPG. Running Premium.