The Ford F-100, part of the fourth generation of the F-Series (1961-1966), represented a significant evolution in Ford’s light-duty truck offerings. Produced from 1965 to 1966, the F-100 with the 3.9L (240 cubic inch) inline-six engine and four-wheel drive was a workhorse aimed at buyers needing a capable and relatively affordable pickup. This configuration, producing 150 horsepower, occupied a middle ground in the F-100 lineup, offering a balance between power, fuel economy, and cost. It was positioned below the larger V8 options, appealing to those whose needs didn’t demand the extra performance, but still required the versatility of a four-wheel-drive system.
Technical Specifications
| Brand | Ford |
| Model | F-Series F-100/F-150 |
| Generation | F-Series F-100 IV |
| Type (Engine) | 3.9 240 Six (150 Hp) 4WD |
| Start of production | 1965 |
| End of production | 1966 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 2-3 |
| Doors | 2 |
| Fuel Type | Petrol (Gasoline) |
| Power | 150 Hp @ 4000 rpm |
| Power per litre | 38.1 Hp/l |
| Torque | 317 Nm @ 2200 rpm / 233.81 lb.-ft. @ 2200 rpm |
| Engine layout | Front, Longitudinal |
| Engine displacement | 3933 cm3 / 240.01 cu. in. |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 101.6 mm / 4 in. |
| Piston Stroke | 80.77 mm / 3.18 in. |
| Compression ratio | 9.2:1 |
| Fuel injection system | Carburettor |
| Engine aspiration | Naturally aspirated engine |
| Max. weight | 2540 kg / 5599.74 lbs. |
| Trunk (boot) space – minimum | 1274-2163 l / 44.99 – 76.39 cu. ft. |
| Length | 4630-5138 mm / 182.28 – 202.28 in. |
| Height | 1905 mm / 75 in. |
| Wheelbase | 2921-3277 mm / 115 – 129.02 in. |
| Front overhang | 780 mm / 30.71 in. |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels permanently, and the front wheels are driven through an electrically or mechanically operated clutch if necessary. |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 4 gears, manual transmission |
| Front suspension | Independent coil spring |
| Rear suspension | Leaf spring |
| Front brakes | Disc |
| Rear brakes | Drum |
| Tires size | 215/75 R15; 225/75 R15 |
| Wheel rims size | 7J x 15 |
Powertrain & Engine Architecture
The heart of this F-100 variant was the 3.9-liter (240 cubic inch) inline-six cylinder engine. Designated within Ford’s engine family as the 300 cubic inch family, despite its smaller displacement, it shared many components with its larger siblings. This engine utilized a cast iron block and cylinder head, a configuration known for its durability. Fuel delivery was managed by a single-barrel carburetor, a common setup for the time, prioritizing simplicity and cost-effectiveness over outright performance. The engine featured a 9.2:1 compression ratio and a relatively mild camshaft profile, contributing to its smooth operation and reasonable fuel consumption. The four-wheel-drive system employed a mechanically operated transfer case, allowing the driver to switch between two-wheel drive and four-wheel drive as needed. The four-speed manual transmission was a robust unit, designed to handle the engine’s torque and the demands of work-related tasks.
Driving Characteristics
The 150 horsepower and 234 lb-ft of torque provided by the 3.9L engine and four-speed manual transmission resulted in adequate, but not exhilarating, performance. Acceleration was modest, and the truck was not designed for rapid speeds. However, the engine’s torque curve was relatively flat, providing usable power across a wide RPM range. This made it well-suited for hauling loads and navigating challenging terrain. The four-wheel-drive system significantly enhanced traction in slippery conditions, making the F-100 a capable off-road vehicle. Compared to the V8-powered F-100s, this variant offered a more economical driving experience, but at the expense of outright power and towing capacity. The manual transmission provided the driver with greater control over gear selection, allowing for optimal engine braking and power delivery in various situations.
Equipment & Trim Levels
The 1965-1966 F-100 4WD with the 3.9L engine typically came with a fairly basic level of equipment. Standard features included a simple dashboard with basic gauges, a vinyl bench seat, and a heater. Power steering and power brakes were often optional extras. Interior trim was generally utilitarian, focusing on durability rather than luxury. Buyers could choose from a limited range of exterior colors. Optional equipment included a radio, a cigarette lighter, and upgraded interior trim packages. The trim level was generally considered a step above the base models, but below the more luxurious Custom Cab options.
Chassis & Braking
The F-100’s chassis was a traditional body-on-frame construction, providing a robust and durable platform. The front suspension utilized independent coil springs, offering a relatively comfortable ride. The rear suspension employed leaf springs, which were well-suited for carrying heavy loads. The braking system consisted of disc brakes on the front wheels and drum brakes on the rear wheels. While adequate for the time, the braking performance was not particularly strong by modern standards. The 4WD system added significant weight and complexity to the chassis, requiring a more robust suspension and drivetrain components.
Market Reception & Comparison
The F-100 3.9L 4WD was generally well-received by buyers who needed a capable and affordable pickup truck. Critics praised its durability and versatility, but noted its lack of refinement and relatively modest performance. Compared to the V8-powered F-100s, this variant offered better fuel economy and a lower purchase price. However, it lacked the towing capacity and overall power of its larger-engined siblings. The 3.9L engine was considered a reliable and long-lasting powerplant, making this F-100 a popular choice for those who prioritized dependability over outright performance.
Legacy
The Ford F-100 3.9L 4WD has become a popular choice among classic truck enthusiasts. Its simple design and durable construction make it relatively easy to maintain and repair. The 3.9L inline-six engine is known for its longevity, and many examples are still on the road today. While not as sought-after as the V8-powered models, the 3.9L 4WD F-100 offers a unique combination of affordability, capability, and classic Ford styling. In the used car market, well-maintained examples command reasonable prices, making them an accessible entry point into the world of classic Ford trucks. The enduring popularity of the F-Series, and this variant in particular, is a testament to Ford’s commitment to building durable and reliable work vehicles.
