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What Is A Ford F250 HighBoy?
In the last sixties, Ford introduced the fifth generation of F-series trucks and decided to include a divorced T-case (Dana 24, NP203, or NP205) for its 4x4 models. The transfer case was bulkier than others, needing to sit farther back, and its installation required much more room in the front end. Since Ford’s designers couldn’t fathom a truck with its nose pointed into the air, they incorporated a 4” lift block on the rear end. While Ford knew that the 4x4 transfer case would raise the height of their truck, they didn’t mind standing taller than their competition (both figuratively and literally).
In the late 50s, Ford realized that truck owners wanted a truck capable of handling rough terrain. Though Ford had extensive experience manufacturing 4WD Jeeps in the 40s (many were used in the War), the company had chosen to stick with a basic 4x2 drivetrain for their new F-series (F100 in 1948). Instead of offering an integrated 4WD option, Ford had been farming out 4x2s to Marmon-Harrington and other subcontractors for the conversion. Owners who wanted 4-wheel drive had to convert their 4x2s until 1959 when Ford started offering an integrated system at the factory. (The system wasn’t new, just an adaptation of older 4x2 conversion methods).
In 1967, the F-Series trucks undertook a radical shift in power and performance. Big-block motors like the 360 and 390 V8 were installed to improve engine capacity (Ford put these engines in full-sized cars like the Mustang, the LTD, or Lincoln Continental).
Since Ford lengthened their truck by about 4 inches, which required more substantial leaf springs and a new rear axle. Interior comforts like an upgraded bench seat, power brakes, and a refined dash pushed production costs to the limit. Ford decided to use a separate transfer case rather than redesigning an adapter to marry the transmission simply to save money.
Eventually, Ford stopped using this system almost a decade later because many owners complained that the higher truck was difficult to climb into. In addition, truck owners couldn’t buy a 4WD F 250 with a Camper Special Package, due to concerns about the higher center of gravity might mean the truck could tip over.
Who Started the Name “HighBoy”?
The first use of the term “Highboy” has its roots in 1928 - 1932 when it was used to describe hotrod cars that had shed their fenders and bumpers to expose the inner frame. While some farm equipment may have carried the designation, the term isn’t used in any officially produced Ford literature. When Ford abandoned the separate transfer case in the second half of 1977, owners quickly labeled the new 4X4 as a “lowside.” Ford started using married systems in 1975 (first in F100s and F150s and eventually making the change in F250s. (According to
Fordification's sales figures showed a 36% increase in truck sales in ‘76).
What Transfer Cases Did the Highboy Use?
Ford used three transfer cases during the Highboy run, the Dana 24, NP205, and NP203.
Dana 24
The Dana 24 was Ford’s standard divorced transfer case in F250/F350s from 1959 - 72. (It also appeared in the ‘59 - ‘66 F100s and 73 - 75 F100/150s). It was a part-time 2-speed unit (hi-lo) made of cast iron. The gear-driven case had a lower gear ratio of 1.86:1, which provided more torque than previous versions, but tended to suck gasoline like nobody’s business.
The main advantage to the case was they were almost indestructible (an iron case could be the reason). These transfer cases could withstand the abuse many truck owners were putting their trucks through. However, they tended to wear out the drivetrain prematurely under heavy towing loads. The reason is that most Dana 24s used in ‘73 - ‘77 models did not have a strut rod, making the towing experience jerky (which confounded many owners), and placing undue strain on the transmission and drive axles.
Most Ford forums will tell you that Dana 24s are almost impossible to find (let alone get replacement parts). The primary problem existing Dana 24s have are worn-out pocket bearings in the 2-piece main shaft. Many restorers have opted for the NP205, which bolts right in.
NP205
The New Process Gear 205 transfer case was offered on the Ford F 250 4x4s from 1973 to ‘77. (The NP205 has a proven track record in other trucks, most notably certain Chevy pickups (‘71 - ‘79) and Dodge 4x4 trucks (‘72 - ‘74). While the NP205 weighed more and was a bit larger, the low gear ratio was similar (1.96:1). The transfer case had four shift positions, 4W Hi, 4W Lo, 2W Hi. and Neutral.
The heavy-duty gear-driven case was built in Syracuse, NY, and shipped to Ford’s assembly plant for installation. Ford used a driver’s side front output for several years before “marrying” the NP205 in 1977 with a new six-bolt pattern that could bolt right onto the transmission. NP 205s are easy to identify due to the id tag above the output shaft, which lists the serial number and date of manufacture.
Ford solved their towing issue by adding a solid strut rod, and this transfer case is the choice of many classic car restorers. Due to the prevalence of the T-case, aftermarket parts are easy to find. Many high-mileage NP 205s will exhibit issues of popping out of low gears and should be inspected for broken or worn needles.
NP 203
The NP 203 transfer case was a full-time chain-driven unit that could be locked into a part-time case. The cast-iron case was solid and durable but significantly more extensive than the NP 205. The low gear ratios were almost identical (NP205 - 1.96:1, NP203 - 2:1).
The NP 203 was available as an option for automatic transmissions from ‘73 - ‘77 as a divorced unit and then married in (‘77 - ‘79). Since only around a third of the F250s sold during these years were four-wheel drive trucks, the NP 203 is relatively rare.
What Engines Came in the Ford F 250 Highboys?
Several engine options were offered for the Ford F 250 during the Highboy years. In 1967, for the F 250 truck, there were two choices of inline six motors (240 ci and 300 ci). Ford touted these straight sixes as “high displacement” engines, designed to be run on the highway, without losing fuel economy. Hydraulic lifters and aluminum pistons helped keep the motor quieter.
The optional Big=block 352 V8 topped out at 208 HP and 310 lb/ft of torque, which for the day was impressive. But its life was short-lived as the company put the 360 V8 in the next year.
The 360 V8 was the bread-and-butter motor for most Ford F 250 4x4s (although the 1968 sales brochure offers the 390 V8 as an option, for 2WD models). The 360 had 215 HP and 443 lb/ft of torque, and most owners opted for the larger powerplant to perform the tasks they needed.
In 1977, Ford experimented with a 400 ci V8, but after 1977.5 made the transition to the small-block V8s, like the 351M to ease fuel economy issues.
What Transmissions Were Found in Ford F 250 Highboys?
There were three primary transmissions used during the Highboy era. The 3-speed manual and NP435 4-speed were offered from 1967 through 1977, but from 1973 on, most of the units had the SelectShift automatic with a C6 transmission. The downside of early F250 4WD was that you couldn’t get them with Cruise-OMatic.
