Back when the 1951 Dodge B-Series pickup rolled out of the factory, nobody really cared about truck fuel economy. At least, little more than they cared about the fuel economy of tractors and lawnmowers. But these days, classic pickups like these are almost as popular as daily drivers as any muscle-era screamer; and that makes getting an estimate on fuel economy a slightly more relevant subject.
What You Can Expect
The federal government didn't keep track of fuel economy before the 1980s, which makes economy figures on even some of the more popular cars a little hard to come by. Economy figures for original trucks are almost nonexistent -- but we can use some existing information to extrapolate a rough economy figure. The 1950 Dodge Coronet station wagon weighed about the same as a full-sized B-Series pickup, it used the same flathead, inline-six engine and similar transmissions. The Coronet wagon was good for about 10 to 13 mpg in the city, and 16 to 20 mpg on the highway. The Dodge pickup was taller, so it might have somewhat lower highway fuel economy; however, owner-built trucks with larger, newer, rebuilt 318 V-8 engines are reported to have cracked 22 to 24 mpg on the highway. Similar Ford trucks from the era have been known to average between 18 and 20 mpg, so about 18 to 20 mpg is about what you can expect for a stock restoration 1951 Dodge B-Series in excellent condition.