From 1973 to 1987, General Motors built millions of the most beloved light trucks in North America. Enthusiasts call these familiar machines the Square Bodies. 

We’re not sure anyone predicted this at the beginning, and the trend developed right under our noses, but one of the more popular enthusiast vehicles in America these days isn’t a car, it’s a truck. We’re talking about the 1973-87 Chevy and GMC pickups and SUVs—the ones that have come to be known as the Square Bodies. And you can find enthusiasts enjoying their Square Bodies in nearly every form of automotive pastime, from drag racing to autocross to mud bogging. Some owners even carefully restore them to factory original. These trucks are ubiquitous. We see them everywhere.

And when we think about it, it’s easy to see how the Square Bodies became so popular with the hot rod and modder crowd. Through the ’70s and ’80s, as passenger cars grew more complicated and fussy, the trucks remained simple, rugged, easy to repair and modify. They were offered in a multitude of engine and drivetrain combinations: inline six, V6, small-block and big-block V8s, diesels. And the body styles and trim levels are almost endless: pickup, Blazer, Suburban, Stepsides, Crew Cabs, Dualies. For Square Body enthusiasts, the possibilities are almost infinite.

This 1973 Chevy C10 Stepside, above, is typical of the factory sport editions often  offered through the years, with special vinyl graphics and a dressy wheel-and-tire combination. In those days it was all about choice. There were 15 standard exterior colors and the whole armada of Chevy engines for ’73, from the stovebolt six and small-block V8s to the mighty 454 CID big-block V8, although the 454 was limited to 230 hp by the emissions technology of the day.

At the opposite end of the Square Body spectrum, if you will, is this 1987 GMC 3500 Wideside Crew Cab. With its dual-wheel rear axle and severe-duty running gear, it was ideal for construction work and for serious towing. (Back in the day, these rigs were especially popular with racers—they were perfect for pulling fifth-wheel race car trailers.) At times, Chevrolet used the name “3+3” for the four-door cab style and “Dooley” for the dualie rear axle in its marketing materials. Meanwhile, the smooth Styleside pickup bed style was sometimes called a “Wideside” in GMC advertising.

The GM Square Body platform was also the basis for the popular second-generation Chevy Blazer, which was badged as the Jimmy in the GMC dealer channel. (1978 Blazer K5 shown above.) Until 1975 the Blazer/Jimmy offered a removable convertible top, and there was a removable cap section after that. The short-wheelbase SUV enjoyed a somewhat longer production life than the rest of the Square Bodies. It hung on through 1991 while the rest of the platform family was replaced with the GMT 400 series after 1987.

Like all the Square Bodies, this 1983 GMC Suburban (above) was available in both 2WD and 4WD versions and in a wide range of gross vehicle ratings. And apart from their nameplates, the Chevrolet and GMC Suburban Squares were for the most part identical. (GMC didn’t drop the Suburban badge until 2000.) While the cabins on these truck-wagon hybrids weren’t quite luxurious, they were available with nearly every comfort and convenience option.

As we can see with this 1987 Scottsdale pickup below, the Square Body family of trucks went through only minor sheet metal changes over the 15-year production cycle. Rectangular sealed-beams replaced the traditional round headlights in 1980, the front doghouse was treated to a minor restyling for 1981, and there were subtle grille and trim tweaks through the years. That’s a remarkably long life for a vehicle platform in modern times.

It’s interesting to note that while we call these trucks Square Bodies, the styling theme was called “rounded-line” inside the GM design studios. Whatever you call it, it’s a simple, classic look. Another interesting note: The Square Body era at GM continued through the reigns of three GM design vice presidents: Bill Mitchell, Irv Ribicki, and Chuck Jordan. It brings to mind an old adage: When you’ve got something good, try not to mess with it.