How many miles per gallon does the old Bronco get?
The original Ford Bronco, built from 1966 through 1977, typically delivers between about 12 and 18 miles per gallon, with higher numbers from inline-six engines and lower numbers from V8s. Real-world fuel economy varies widely based on engine choice, drivetrain, gearing, and condition.
Exploring these numbers offers a practical look at what owners of classic Broncos should expect today. The following sections detail how engine choices, configurations, and maintenance influence mpg on these vintage off-road vehicles.
What factors affect mpg in the early Broncos
Fuel economy on the early Bronco is driven by several interacting elements. Here's how they typically impact mpg:
Engine choice is the largest determinant of mpg, followed by drivetrain setup, transmission, tire size and lift, and ongoing maintenance. Real-world results depend on how the vehicle is equipped and how it’s driven.
- Inline-6 engines (e.g., 170 CID or 200 CID): roughly 15–22 miles per gallon on highway driving; around 12–16 miles per gallon in mixed or city conditions.
- V8 engines (e.g., 289, 302, 351 Windsor): commonly 12–18 miles per gallon overall, with highway runs often in the 15–20 mpg range depending on gearing and load.
- Note: The light-to-moderate weight of early Broncos helps, but boxy aerodynamics and off-road gearing can still limit efficiency, especially with larger tires or four-wheel-drive engaged.
Engine options and rough mpg ranges (typical real-world figures):
In practice, the exact mileage you’ll see depends on how the Bronco is built and used. A well-tuned inline-six with efficient gearing and steady highway speeds will typically outperform a V8 loaded with off-road equipment.
Auxiliary factors that influence fuel economy
The following factors can significantly push mpg up or down, regardless of engine type:
- Drivetrain and gearing: Two-wheel-drive Broncos generally sip less fuel than four-wheel-drive versions; lower overall gearing (smaller rear-end gear, or taller final drive) improves highway efficiency but can hurt off-road capability.
- Transmission type: Manuals and automatics from the era behave differently; manuals often feel more economical in steady cruising, while automatics may trade some efficiency for convenience, depending on the torque converter and gear ratios.
- Tire size and suspension modifications: Larger tires, aggressive tread, and lift kits increase aerodynamic drag and rolling resistance, reducing mpg.
- Weight and equipment: Roof racks, winches, heavy bumpers, and other mods add weight and air disturbance, lowering fuel economy.
- Maintenance and tuning: Proper carburetion or fuel delivery, ignition timing, and engine tune-ups can markedly improve performance and efficiency for a vintage carbureted setup.
Pre-list context: These items explain why two Broncos with the same engine can have different mpg numbers.
Because these trucks were built with different options and over a long production span, owners report a wide range of real-world numbers. A stock-like six-cylinder Bronco kept in good tune will usually perform better on highway trips than a heavily optioned V8 with oversized tires.
Summary
In short, the old Ford Bronco’s mpg sits roughly in the teens, with inline-sixes toward the higher end and V8s toward the lower end. Expect about 12–18 mpg overall, with highway figures in the mid- to upper-teens for V8s and highs teens or low 20s for well-tuned inline-sixes on open roads. Modifications, drivetrain choice, and driving style all swing the numbers a lot in this era of vehicles.
Bottom line
Anyone restoring or driving a classic Bronco should consider fuel economy as a secondary concern to reliability and enjoyment. If mpg matters, plan for a range rather than a precise figure and factor in maintenance, tire choices, and gearing when estimating real-world fuel costs.
Summary of key mpg drivers for the old Bronco
The most influential factors are engine type, four-wheel-drive configuration, tire size, and overall vehicle weight from added equipment. Inline-sixes tend to be more efficient than V8s, while off-road gear typically lowers mpg. With careful maintenance and sensible modifications, a Bronco can be more fuel-efficient on highway runs than its curb weight might suggest, but it will rarely rival modern SUVs in efficiency.
