The Ford F-series is the best selling truck in automotive history. Ford trucks are one of the most iconic vehicles in the world. The modern F-250 is the dominant force in the American truck war. The new Ford 4x4s boast 8.8-inches of ground clearance and an electronic shift-on-the-fly transfer case. But there was a time when the American automakers did not even offer four-wheel-drive trucks. We're remembering a pioneer: The lifted, four-wheel-drive Ford highboy.
A Divorced Transfer Case Explained
Ford had a problem. Truck buyers wanted a 4x4. Thanks to the WW2-developed Willys Jeep and Dodge Powerwagon, American drivers were catching the offroading fever. But Ford's rear-wheel-drive F-series was a reliable workhouse and the bestselling truck around. Ford couldn't risk--or afford--redesigning the entire drivetrain. They could buy front axles from the Dana company, but their 2wd Ford transmissions had no transfer case to spin a forward driveshaft.
Ford's solution was known as a divorced transfer case. The automaker built their 4wd F-250s with normal, 2wd transmissions. The transmission drove a short driveshaft which ended at a mid-truck transfer case. This transfer case spun a regular, rear driveshaft. And when engaged, the transfer case also spun a long, forward driveshaft.
Ford's divorced transfer case solution had a single downside: the exceedingly long front driveshaft required much more clearance than stock Ford trucks offered. Until Ford introduced an integrated transfer case in the second half of 1977, their 4x4 pickups had to ride 5 to 6-inches higher than similar 2wd trucks. This generation of F-250 4x4s has become known unofficially as the Ford highboy.
The Definition Of A Highboy
Highboy is a nickname for a 1967-1977 four-wheel-drive F-250. Ford has offered factory four-wheel-drive trucks since 1959. Their first 4x4s also had a divorced transfer case, and thus a higher stance. But in 1967 Ford launched the distinctive, and beloved, fifth generation of the Ford F-series. For this reason, only the 1967-1977 Ford F-250 4x4s have been nicknamed highboys. One famous highboy is Bob Chandler's original Bigfoot.
Between 1967 and 1977, Ford also offered four-wheel-drive F100 trucks. These trucks sat almost two inches lower than their F-250 counterparts. Some enthusiasts refer to the fifth-generation F100s equipped with 4wd as highboys. Other fans reserve the term highboy for the F-250s. The F150, a perfect combination of power and utility, wouldn't be introduced until 1975. This article will only cover the 1967-1977 F-250.
Highboy Axles And Suspension
The 4x4 Ford F-250 highboys all used Dana front axles. These trucks were outfitted with either 8-lug Dana 44, Dana 44HD, or Dana 60 axles. All axles were low pinion. The front axles rode on 3-inch-wide leaf springs. Front spring bundles included 5 or 6 leaves. The way Ford achieved a suspension lift was to arch the highboy front leaf springs much more dramatically than the 2wd springs. Ford did not offer front disc brakes on its F-250 trucks until 1975. Ford did offer power brakes as early as 1973.
Ford equipped fifth-generation F-250s with 16 or 30-spline Dana 60 rear axles. Highboy axles were set up with a 4.10:1 gear ratio. All rear axles came with drum breaks and eight-lug bolts. The rear of the F-250 frame sat on 2-1/4" wide springs consisting of nine leaves. These rear springs were narrower than the 3" springs found on contemporary 2wd Fords. The highboy rear ends were lifted with a 4-inch block. Many modern offroad enthusiasts scoff at body lift kits that raise a vehicle's ride height with only suspension blocks. But in the 1960s, Detroit engineers obviously disagreed with this opinion. Read more about highboy history on BlueOvalTrucks.com.
Divorced transfer cases found in a highboy were a Dana 24, NP203, or NP205. By the mid-1970s, competitors' low and comfortable 4x4 trucks were hurting Ford sales. Halfway through the 1975 model year, Ford introduced a transmission with an integrated transfer case. The transmission/transfer case was a major event in the evolution of the Ford F-150. The new F-250 trucks used a much shorter forward driveshaft and thus could sit much lower. Ford did away with the rear lift block and the dramatically bent front springs to lower its 1975.5 4x4 trucks. After the introduction of these new, low 4x4s, the older generation of 4wd Fords became known as the highboys.
Fifth Generation F-250 Powertrains
During its ten year production, the Ford F-250 highboy was offered with a range of powertrains. From 1967-71, customers could purchase Ford highboys with a "Toploader" 3-speed manual. For the entire 1967-1977 life of the highboy, Ford offered the truck with their NP-435 4-speed manual transmission. In 1973 Ford began installing automatic transmissions in the F-250 highboys: the SelectShift Cruise-O-Matic C6. In 1973 Ford also increased the truck's wheelbase from 133-inches to 150-inches.
From 1967-1974, Ford customers could order their highboy with a 240 cubic inch six-cylinder engine. Every year of highboy was available with a 300 cubic inch six-cylinder. Ford's famous 360 V8 was also available in nearly every year of the highboy: from 1968 through 1975. For this reason, there is a common myth that any V8 highboy is powered by the 360. In truth, Ford experimented with putting three additional V8 engines in the highboy--each for one year only: The 352 V8 in 1967, the 351M V8 in 1977, and the 400 V8 also in 1977.
Despite offering highboys with massive V8s, Ford reported concern selling the top-heavy trucks with a high center of gravity. They never offered a "camper special" option on the highboy, urging their customers not to install campers over their 4x4 trucks.