Why Is The Ford 427 V8 Engine Called The Side-Oiler?

In terms of sheer horsepower, the 1960s were truly the golden decade for American cars. Car manufacturers were locked in fierce competition, challenging what was possible both on the streets and the track. And speaking of racetracks and competitions, there was no battleground more prestigious than the legendary 24 Hours of Le Mans. It was against this backdrop that Ford developed one of the most iconic engines in motorsport history: the 427 cubic-inch V8.

Now, the story of how the Ford 427 came into existence makes it all the more interesting. It started with a personal vendetta. After a failed bid to purchase Ferrari, Henry Ford II made it his mission to crush the Italian company that had dominated European endurance racing for six straight years. Ford's goal wasn't to simply compete. He wanted to out-engineer, overpower, and outlast Ferrari on its own turf.

To do that, Ford engineers took their existing FE-series V8 and made several critical modifications, including a key change to the oiling system, which is how the engine earned itself the "Side-Oiler" moniker. While it seemed like a small adjustment, it made a massive difference in durability, ensuring that this American engine could survive the grueling conditions of endurance racing.

This single engineering breakthrough made this one of the most powerful engines ever placed in a pro race car. We'll help break down how the Side-Oiler system worked, why it was special, and how it helped Ford achieve one of the greatest feats in racing history.

In the early years of the Ford 427's development (1963-1965), the engine used a design called the "top-oiler" or "center-oiler." In this setup, oil was pumped first to the valve train components at the top of the engine, and only afterward did it reach the crankshaft and main bearings at the bottom. While this worked fine for street driving and even light racing, it caused problems during high-speed, high-RPM racing. At sustained speeds above 5,000 RPM, the crankshaft and main bearings didn't get enough oil. Under the extreme demands of NASCAR and Le Mans racing, where engines needed to perform flawlessly for hours on end, this oil starvation at the main bearings led to numerous failures that hurt Ford's early racing efforts.

Ford's engineers recognized that this oiling priority needed to be reversed for racing applications. Their solution, implemented after 1965, was to completely redesign the oiling system with a new approach. They added a new oil passage along the left side of the engine block, which sent oil directly to the crankshaft and main bearings first before reaching the valve train. This ensured the most critical parts of the engine were properly lubricated, even under extreme racing conditions. The new design, visible as a raised ridge on the side of the engine block, earned the engine its famous "Side-Oiler" name.

This simple but effective change made the 427 much more reliable in racing, allowing it to perform at high RPMs for long periods without failing. It was a key improvement that helped Ford succeed in motorsports and cemented the 427 Side-Oiler's reputation as a legendary racing engine.

The 427 Side-Oiler quickly became the heart of Ford's most successful racing efforts in the 1960s. With its robust oiling system and high 12.5:1 compression ratio, this powerplant delivered an impressive 475 horsepower that could be sustained throughout long races, which was exactly what Ford needed for endurance racing. This translated directly to victory when Dan Gurney and A.J. Foyt drove their Side-Oiler-powered Ford GT40 MkIV to win the 1967 24 Hours of Le Mans. Notably, this marked the second of four consecutive wins that cemented Ford's legacy as the first American manufacturer to conquer Ferrari on European soil.

Beyond the circuit tracks, this engine also found a home in drag racing, where it powered Ford's Thunderbolt Super Stock cars, challenging Chrysler's 426 HEMI on the quarter-mile. Perhaps most famously, it also became the beating heart of Carroll Shelby's 427 Cobra, one of the fastest and most brutal street cars ever built. However, not all Cobras received the true 427. To cut costs, Shelby often installed the cheaper 428 Police Interceptor engine, rated at only 340 horsepower. When customers noticed the massive performance gap and complained, Shelby discreetly swapped some 428s for proper Side-Oilers.

The Side-Oiler's final form came in the 427 SOHC, better known as the "Cammer." With overhead camshafts and hemispherical combustion chambers, it was a game-changing powerhouse, making up to 657 horsepower with dual four-barrel carburetors. It was so potent it got banned outright, making it the first engine ever banned from a NASCAR competition. Today, cars with original 427 Side-Oiler engines are prized collectibles. Even in not-so-great condition, the 427 Cobra, for instance, can command about $750,000.