Ford’s small-block V-8 engine family has had an impressive and lasting legacy in the automotive world. First introduced in 1962 with the 221-cu.in. V-8, this engine family quickly expanded with more powerful iterations, including the well-regarded 260-cu.in., 289-cu.in., and the legendary 302-cu.in. versions. These engines powered millions of Ford cars, trucks, and vans, serving various roles from reliable family transportation to high-performance racing applications.
Among the most iconic small-block engines was the Boss 302, a high-revving powerhouse that dominated the Trans-Am racing series. On the other end of the spectrum, more pedestrian applications, such as the Mercury Grand Marquis, relied on these engines for smooth, effortless cruising. With a reputation for reliability, performance, and adaptability, Ford’s small-block engines have remained a favorite among enthusiasts, with the 302 still available as a crate engine today.
However, not every small-block Ford enjoyed such a glowing reputation. Among the otherwise stellar lineup, one variant stands out for all the wrong reasons: the 255-cu.in. V-8, produced from 1980 to 1982. This engine, widely regarded as the black sheep of the Ford small-block family, was a compromise built out of necessity rather than performance aspirations.
The 255-cu.in. V-8: An Unfortunate Exception
In the late 1970s, the automotive industry faced tightening fuel economy regulations and increasingly stringent emissions standards. Automakers scrambled to develop solutions that would keep fuel efficiency high while maintaining some semblance of performance. Ford, like its competitors, looked to downsize its engines in response to these regulations. The result was the 255-cu.in. V-8—a desperate attempt to balance economy with the legacy of V-8 performance.
Unlike its predecessors, the 255 was not built with performance in mind. It lacked the robust engineering found in the earlier small-block Fords, and its design choices reflected an era more focused on meeting regulatory demands than delivering power. In a world where the revered 302 could be found under the hood of everything from Mustangs to F-150s, the 255 failed to inspire confidence. The hot-rodding community has all but abandoned it, often recommending replacing it with a 302 rather than attempting to extract any meaningful performance gains.
Design and Characteristics of the 255
At first glance, distinguishing a 255-cu.in. engine from a 302 is difficult. The two engines share many external components, including accessories and overall dimensions, which often leads to confusion. However, a closer inspection reveals several unique features of the 255 that set it apart:
- Intake Manifold and Carburetor – The 255 used an open-runner intake manifold design paired with either a Motorcraft 2150 two-barrel carburetor or, for California-specific models, a variable-venturi carburetor. This setup was intended to optimize fuel economy rather than maximize airflow or power output.
- Cylinder Heads – One of the most significant differences lies in the cylinder heads. Unlike traditional small-block Ford engines that utilized rectangular intake ports, the 255 featured oval intake ports. While this may not seem like a major issue at first, it severely limited airflow, further choking the engine’s potential. Additionally, the 255’s cylinder heads (E0SE-AB) had smaller combustion chambers (53-56cc) than the D9AE 302 heads, which had 67-70cc chambers.
- Valvetrain and Bore Size – The 255’s smaller bore diameter meant that it could not accommodate the larger valves found on the 302. While the 302 utilized 1.780-inch intake valves, the 255 had to make do with smaller 1.680-inch intake valves. The restrictive heads and intake manifold, combined with the smaller bore, resulted in an engine that struggled to breathe, producing a disappointing power output of around 120 horsepower.
- Crankshaft and Internal Components – The 255 utilized a hollow-core nodular iron crankshaft, designed to reduce rotational mass and improve efficiency. While this crankshaft was about five to six pounds lighter than the standard 302 crankshaft, it was met with skepticism within the Ford performance community. Many enthusiasts questioned its durability, opting to avoid the 255 altogether in favor of more proven small-block variants.
The Limitations of the 255 V-8
The Ford 255’s lack of power and breathability made it an unpopular choice among enthusiasts. Designed to meet emissions regulations rather than deliver performance, it was saddled with numerous limitations:
- Restricted Intake and Exhaust Flow – The combination of small valves, restrictive intake manifold, and oval ports meant that airflow was severely limited. Unlike the free-breathing 302, the 255 struggled to produce adequate power.
- Low Compression and Emissions-Focused Tuning – While some small-block Fords benefited from higher compression ratios to enhance performance, the 255 was tuned for efficiency and emissions compliance. This further reduced any potential for high-output applications.
- Lack of Aftermarket Support – Unlike the 302, which enjoys a vast aftermarket of performance parts, the 255 has virtually no dedicated upgrades. Most enthusiasts who find themselves with a 255 opt to swap it out for a more capable small-block Ford engine rather than attempt modifications.
Can the 255 Be Improved?
If you own a functioning 255 and have no interest in high-performance modifications, then regular maintenance should keep it running reliably. The engine was built to offer decent fuel economy and low emissions, which it did successfully for its time. However, if you’re considering any sort of performance build, replacing the 255 with a more capable engine is almost always the recommended course of action.
While it’s technically possible to modify a 255, the investment required to overcome its inherent design limitations makes it impractical. For those seeking more power, swapping in a 302 is a far simpler and more effective solution. Ford itself recognized this when it phased out the 255 in mid-1982, replacing it with the much more capable 302 V-8.
The End of the 255 and Its Legacy
By the time Ford discontinued the 255 in 1982, it had already gained a reputation as one of the most lackluster engines in the company’s history. Ford’s solution was to bring back the proven 302, now marketed as the “5.0-liter” to align with contemporary naming trends. The 302 was paired with either an overdrive automatic transmission or a four-speed SROD manual with overdrive in fourth gear to improve fuel efficiency while still providing the power expected from a V-8.
Today, the 255 remains largely forgotten, relegated to the annals of automotive history as a smog-era compromise rather than a performance icon. Few examples remain on the road, as many owners have opted for engine swaps over restoration.
Conclusion
The Ford 255-cu.in. V-8 is an oddity in the history of small-block Ford engines. Designed as a response to fuel economy concerns and emissions regulations, it lacked the power and versatility that made other small-block Fords legendary. With its restrictive cylinder heads, underwhelming performance, and lack of aftermarket support, the 255 never found favor among enthusiasts.
While it served its purpose in the early 1980s, the 255 ultimately proved to be a short-lived experiment. Its discontinuation in favor of the 302 only reinforced the idea that small-block Fords were meant to deliver both power and reliability—something the 255 could never quite achieve. For collectors and restorers, the 255 may hold some niche appeal, but for most Ford enthusiasts, it remains little more than a historical footnote in an otherwise successful engine lineage.
