1951 Cadillac coupe getting service in N. Austin, Texas. Its modern OHV 331-cid V-8 makes 160 hp. Compared to the flathead V-8 it replaced in 1949, it’s more compact, weighs 188 lbs. less, and is more powerful. Because gasoline was now available with higher octane, compression ratios could be raised, too. Popular Mechanics reported about 12 mpg at 45 mph.