The Ford F-Series F-100, specifically the variant equipped with the 3.9-liter (240 cubic inch) inline-six engine producing 150 horsepower, was a mainstay of Ford’s light-duty truck lineup from 1966 to 1972. This generation, often referred to as the “Fifth Generation” (though Ford didn’t formally use generation names at the time), represented a significant step forward in comfort and capability for the American pickup truck. Positioned as an entry-level or mid-range option within the F-100 series, it offered a balance of affordability and utility, appealing to farmers, tradesmen, and general-purpose vehicle buyers. It shared its basic platform with the F-150, which was introduced in 1973, effectively replacing the F-100 in the lineup.
Technical Specifications
| Brand | Ford |
| Model | F-Series F-100/F-150 |
| Generation | F-Series F-100 V |
| Type (Engine) | 3.9 240 Six (150 Hp) |
| Start of production | 1966 |
| End of production | 1972 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 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 | 2268 kg / 5000.08 lbs. |
| Trunk (boot) space – minimum | 1274-2163 l / 44.99 – 76.39 cu. ft. |
| Fuel tank capacity | 74 l / 19.55 US gal | 16.28 UK gal |
| Length | 4636-5138 mm / 182.52 – 202.28 in. |
| Wheelbase | 2921-3327 mm / 115 – 130.98 in. |
| Wading depth | 658-660 mm / 25.91 – 25.98 in. |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 3 gears, manual transmission |
| Front suspension | Independent coil spring |
| Front brakes | Drum |
| Rear brakes | Drum |
| Steering type | Cone worm with recirculation balls |
| Power steering | Electric Steering |
| 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 Ford 3.9-liter (240 cubic inch) inline-six engine. Designated internally as the 300 cubic inch family, this engine was known for its durability and relatively simple design. While the 300 cubic inch version was more common, the 240 offered a lighter-weight and more economical option. The engine utilized a cast iron block and cylinder head, and featured a two-barrel carburetor for fuel delivery. The valvetrain employed a single overhead camshaft, operating pushrods to actuate the valves. The 150 horsepower output was achieved at 4000 rpm, while peak torque of 234 lb-ft arrived at a relatively low 2200 rpm, making it well-suited for hauling and towing. The standard transmission was a three-speed manual, though a three-speed automatic transmission (Fordomatic) was available as an option. The engine was mounted longitudinally in the chassis, driving the rear wheels.
Driving Characteristics
The 150 hp 3.9-liter engine in the F-100 provided adequate, but not exhilarating, performance. Acceleration was modest, and passing maneuvers required planning. Compared to the larger 390 cubic inch V8 options available in the F-100, the 240 six-cylinder was noticeably slower. However, the lower engine weight contributed to better handling and fuel economy. The three-speed manual transmission offered precise control, while the optional automatic provided convenience, albeit at the expense of some responsiveness. The gear ratios were optimized for low-end torque, making it capable of handling moderate loads. The overall driving experience was typical of a 1960s-era pickup truck – robust, utilitarian, and focused on practicality rather than refinement.
Equipment & Trim Levels
The F-100 with the 3.9-liter engine typically came with a fairly basic level of equipment. Standard features included a simple vinyl bench seat, a basic instrument cluster with speedometer, fuel gauge, and ammeter, and a two-spoke steering wheel. Optional extras included a radio, heater, and upgraded interior trim. Trim levels were relatively limited; buyers could choose from a range of paint colors and exterior finishes. The “Custom Cab” option added features like improved sound insulation, a dome light, and upgraded upholstery. The focus was on providing a functional and durable work truck, rather than a luxurious passenger vehicle.
Chassis & Braking
The F-100 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 for a truck of its era. The rear suspension consisted of leaf springs, designed to handle heavier loads. Braking was accomplished via drum brakes on all four wheels. Power steering was an available option, making maneuvering easier, particularly at low speeds. The tires were typically bias-ply, with sizes ranging from 215/75R15 to 225/75R15. The steering system employed a cone worm and recirculating ball mechanism.
Market Reception & Comparison
The F-100 with the 3.9-liter engine was generally well-received as a practical and affordable work truck. Critics acknowledged its durability and fuel efficiency, but noted its lack of power compared to the V8 options. It was often seen as a good choice for buyers who didn’t require the extra capability of a larger engine. Compared to the Chevrolet C10 and Dodge D100, the F-100 offered a similar level of performance and features. The Ford’s reputation for reliability and readily available parts contributed to its popularity. Fuel economy was a strong point for the 240 six, offering better mileage than the larger displacement engines.
Legacy
The Ford F-100 with the 3.9-liter inline-six engine has become a popular choice among classic truck enthusiasts. The engine’s simplicity and durability make it relatively easy to maintain and repair. While not a high-performance machine, it offers a charming and authentic driving experience. Parts availability remains good, thanks to the large number of these trucks that were produced. Today, well-maintained examples command reasonable prices in the used car market, appealing to collectors and those seeking a classic American pickup truck. The 3.9-liter engine, while not as celebrated as the larger Ford V8s, remains a testament to the company’s commitment to building durable and reliable work vehicles.
