The early days of NASCAR involved a paper-thin rulebook that gave engineers and crew chiefs quite a lot of wiggle room to misbehave. The most notorious of these was Henry “Smokey” Yunick, who is credited for most of the thickening of that rulebook since then. He was a stock car racing crew chief, builder, driver, engine builder, and car designer, but an engineering genius first and foremost. He turned stock car racing on its head during the 1960s thanks to his bold—often blatantly outside-the-box—interpretations of the rules and regulations governing car setup.

“Cheating” is ubiquitous in motorsport; I’ve included the quotation marks only because this isn’t a reference to blatant disregard of the rules. Rather, it’s a reference to engineers’ clever readings of the rulebook. The saying “If you ain’t cheating, you ain’t trying,” is often thrown around in sports circles and is still applicable in motorsport. However, Smokey Yunick didn’t make a name for himself by cheating and blindly hoping that nobody would notice. He took the regulations very literally; anything they didn’t explicitly forbid was on the table. What’s more, he didn’t have any formal training in race car design. Call his fiddling hacks if you want, cheating if you prefer, but here are some of his best.

    Clever Fuel Line

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    NASCAR officials once pulled the fuel tank out of Smokey Yunick’s race car after they suspected it was getting suspiciously good fuel mileage. Much to their surprise, the fuel tank itself was within regulation but was being evacuated via an 11-foot-long fuel line with a 2-inch inner diameter. This meant that Yunick could store an additional 5 gallons—yes, gallons—of gas in the fuel line alone.

    Many NASCAR historians say that Smokey drove all the way back to his nearby shop in Daytona Beach after the tank—still removed from the car—passed a basic visual inspection. Other stories mention him only driving back to his pit box. But, given his antics, we wouldn’t be surprised if either tall tale were true.

    Dribbling Fuel Tank

    1940s male hand pumping

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    Smokey wasn’t spooked after NASCAR figured out his anaconda fuel line. If you could pass technical inspection without officials noticing that things were awry, you were pretty much golden. So he fitted a bigger tank and stuffed a basketball inside it that made up for the difference in volume. Before the race, he would pop the basketball and brim the tank with even more fuel. More fuel means more mileage and less time spent refueling in the pits.

    Freezing-Cold Gas

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    Your parents were right when they told you to fill up your car in the morning when it’s cold. Fuel contracts at lower temperatures, meaning you get more for your dollar. That’s why Yunick cooled down the fuel—so much so that it nearly froze—before filling up his race cars so he could fit more in the tanks and those cars could travel farther than the competition. As the cars logged laps, the fuel would warm up and expand, meaning the drivers could get more mileage out of a regulation-size tank. However, NASCAR caught on, eventually mandating a minimum temperature for race fuel.

    Porting The Exhaust Manifold

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    The 1970s NASCAR rulebook banned engine builders from drilling out the exhaust headers to make the passages bigger. That’s why, instead of using a drill, Yunick ran an abrasive compound through the manifold to expand the ports and passages. There was nothing in the rulebook that said you could do this, but also nothing that said you couldn’t.

    Headers are actually a big deal when it comes to making big power; they capture the exhaust gasses coming from each cylinder and condense the passages down into one or two pipes. Their job is to make it easier to push exhaust gasses out of the cylinder itself. The easier you can extract air out of the cylinder head, the faster you can pack air back in. More air inside the cylinder head means you can add more fuel and spark, therefore getting more power.

    Chevrolet Chevelle Magnum Opus

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    Heading into the 1967 NASCAR season, Yunick had been working hard over the winter months building one of the most technologically advanced stock cars the sport had ever seen—many historians allude to the fact that his Chevy Chevelle was 7:8 scale. However, rather than simply fitting a smaller body over the same chassis, Yunick sculpted the exterior of the existing car to cut through the air more efficiently.

    NASCAR is an abbreviation of the National Association of Stock Car Auto Racing, meaning that every car started out as “stock,” or how you and I could buy it from the dealership. The cars you saw in Yunick’s day were effectively modified street cars. This proved to be a big advantage for getting grassroots competitors involved in racing.

    dick hutcherson and smokey yunick

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    But to Yunick—and just about every other NASCAR crew chief there ever was—playing by the rules meant leaving speed on the table. There’s a lot that isn’t known about his 1967 Chevelle race car, but many say that there isn’t an original panel on it that went unmodified. While it may have looked relatively normal from the outside, it couldn’t have been more different.

    Starting at the front fascia, the bumper was fitted tightly to the front fenders and the hood to optimize aerodynamics—all of the door handles were also filled in and leveled to improve aerodynamics. Yunick completely redesigned the rear suspension with the shock and spring mounted vertically and (critically) behind the rear axle. Compared to the conventional truck-arm setup that the car would’ve had, this setup made it much easier to handle thanks to the longer spring base (or the distance between the springs on the left and right sides of the axle). Lastly, one of the most dramatic changes was that Yunick actually moved the driver position toward the left side of the car to improve cornering on ovals.

    Life After Motorsport

    Smokey had quite the knack for giving NASCAR officials a headache. However, his exploits weren’t limited to just the race track. Far from it. In 1955 he played a key role in developing Chevrolet’s small-block V8 engine—the basic fundamentals of the design are still being used in racing today.

    Further outside the racing circle was the hot-vapor engine, which very nearly revolutionized internal combustion as we know it. Yunick essentially found out that vaporizing the fuel mix lead to higher thermal efficiency, which would produce more horsepower. His radical hot-vapor technology transformed a standard Pontiac Fiero—which produced a geriatric 90 horsepower—into a highly strung tuner car with 250 hp.

    Here’s a taste of what Yunick’s vehicle’s accomplished at the race track

    • Daytona 500 Victory (1961, 1962)
    • Indy 500 Victory (1960)
    • NASCAR Cup Championship (1951, 1953)
    • 57 NASCAR Race Wins

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