Have you ever heard the time-honored adage, “less is more?” Sure, it might seem a little counterintuitive. But, depending on the context, the old phrase has things figured out. Take drag racing, for instance. Granted, you’re going to want herds of horsepower and wide, squishy contact patches to sprint down the strip. But when it comes to gears, sometimes less is more.
Enter the Chevrolet Powerglide transmission. The powers that be at General Motors and Chevrolet wanted the simple, two-speed gearbox to be a cost-cutting means of getting an economical automatic transmission into Chevrolet cars like the Bel Air, Biscayne, and Impala. But remarkably, the rugged, straight-shooting two-speed became something of an icon, especially for drag racing.
Chevrolet Powerglide: Strong And Simple
In 1950, you could get a car from a General Motors subbrand like Oldsmobile with an automatic transmission. What you couldn’t get, however, was a budget-friendly Chevrolet with a simple, affordable automatic gearbox. Then Chevrolet rolled out the first two-speed Powerglide automatic. After 1950, the Bow Tie started putting the Powerglide in the Chevrolet DeLuxe line of sedans, a full year before Ford put its first Ford-O-Matic automatic gearbox in a car. Little did Chevrolet know that the stout, simple design of the two-speed would become a drag racing icon.
A Low-Cost Option For Chevy Cars
At first, Chevrolet intended for the two-speed to be an affordable means to get an automatic into the brand’s passenger cars. To accomplish that task, Chevrolet kept things simple. The first-generation Powerglides were cast iron and assembled using bolts and gasketry. It functioned in a simple manner, too. The early Powerglide-equipped cars would take off in the top gear of the two forward gears. It would only downshift when it needed the extra grunt, like when heading up an incline. Needless to say, the first-gen models weren’t exactly quick from a standstill. By the early 1960s, Chevy went back to the drawing board.
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A Lighter, Stronger Second-Generation
The Powerglide remained mostly unaltered throughout the 1950s. In 1962, Chevrolet rolled out air-cooled versions of the transmissions with a few tweaks. For starters, the then-new Powerglide was aluminum, shaving serious weight compared to the outgoing unit. What’s more, the lightweight rotating assembly does a better job of making sure as much of the engine’s power reaches the wheels as possible, instead of being lost to operating a more complicated gearbox. Then we have the aftermarket. Today, nearly 65 years after the first aluminum Powerglides made it into Chevrolet cars, you can buy crate two-speed automatics from outfitters like TSI with a 1.8:1 first gear ratio rated up to 2,500 horsepower. Not bad for an old-school design. Don’t believe it? Australia’s Rob Campisi managed to run a record-shattering 5.975-second quarter mile at 254 mph using one. Oh, and it was mated up to a 3,000-horsepower 632-cubic-inch big-block Ford V8 at the time.
A Popular Choice For Drag Racers
Some of the swiftest, snappiest new cars on the market have 8, 9, or even 10 gears in their automatic gearboxes. Take the Ford Mustang Dark Horse, for instance. With Ford’s 10R80 10-speed automatic transmission bolted in, the noir pony will hit 60 in around 3.7 seconds on its way to a quarter mile in roughly 12 seconds. Not too shabby. The quick-shifting 10-speed is simply faster than a competent pilot working the standard TREMEC TR-3160 six-speed gearbox. Still, when it comes to custom drag strip-bound race cars, you’ll find no shortage of interest in the old-school two-speed automatic transmission among builders. The reason? Put simply, the second-generation two-speed Powerglide is uncomplicated and immensely durable, two things an asphalt-cracking drag car needs to thunder down the strip consistently and often.
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Taking It To The Track
So, why on Earth would drag racers choose a comparably primitive transmission like a two-speed Powerglide? As previously mentioned, the two-speed Powerglide gearbox is simple. Two gears mean fewer shifts. I don’t have to tell you that any shift is an opportunity to lose traction and slow things down, often at the expense of valuable deciseconds. Two gears also means, well, two gears. During a sprint to the eighth or quarter-mile mark, a drag car with a two-speed Powerglide shifts just once. A longer, taller first gear means a strip-ready car with a monstrously powerful V-8 can smoothly accelerate and put down consistent times. “But it must be so heavy!” You might be surprised. Improvements in engineering and the aftermarket make a difference in the Powerglide’s weight without relinquishing its robustness. When Chevrolet updated the two-speed transmission in the early 1960s, it gave the Powerglide an aluminum treatment. The result? An updated Powerglide shaved around 100 pounds from the gearbox, vital for keeping a drag car’s weight down. But even with the weight-shedding diet, the Powerglide maintained its durability derived from simplicity.
Not Just Drag Racing
What started as an affordable two-speed transmission for the grocery-getters of yesteryear became an American motorsport institution. That said, the Powerglide’s racing résumé doesn’t stop at the drag strip. The simple two-speed transmission’s reputation for robustness has established it as a desirable transmission swap for off-roaders. While the three-speed TH400 or newer 4L60E is a more popular automatic swap for off-roaders, many mud-racers and trail drivers choose the Powerglide for its near indestructibility and consistency. After all, off-roading is often seriously unforgiving, and more gears means more of a chance for things to break or fail.
10 Speeds Too Many
We’ve established that the updated two-speed Powerglide design from the 1960s is a drag racer’s friend. But how could it possibly compete with an eight-speed gearbox as you’d find in a Dodge Challenger SRT Hellcat, or a 10-speed as you’d find in a Chevrolet Camaro ZL1? Great question. To launch as hard and as quickly as possible, modern 10-speed performance cars like the Ford Mustang Dark Horse or the Chevrolet Camaro ZL1 use features like launch control. However, launch control and traction control work by assessing and managing engine power to prevent wheelspin and promote traction. And who wants less power or brake application when you’re trying to charge down the strip? Not to mention the potential for failures with more gears and complicated components. Then you have the Powerglide approach. Specifically, a nearly indestructible two-speed with a tall first gear, a drag strip-happy rear end like a 3.90, and some wide, sticky drag tires. That recipe has the potential for consistent, fast times at the strip.
Sources: CarBuzz, Gearstar, Hemmings, MotorTrend