GMC is known for hard-working trucks that shift bales of hay and keep America moving. But this is not a company you would associate with muscle cars or generally going fast. But one forgotten GMC model from the '70s is the stuff of muscle car nightmares, with the kind of horsepower and torque from big block mills that were up there with some of the lairiest machines of the decade. The only problem is that hardly anyone would remember this muscle car chaser, with production numbers way lower than some more iconic rivals. It's time to revisit this long-forgotten muscle machine. The 1971 GMC Sprint Was A Muscle Car For Trips To The Hardware Store Bring A Trailer Mention a passing interest in "coupe utility" vehicles at a car meet and be prepared for some local pub bore to mansplain the virtues of the Chevrolet El Camino until long after the hot dog stand has been packed away. The iconic El Camino embodies this strange niche of part cars/ part pickup trucks, helped by the 2019 Breaking Bad movie of the same name. There is, of course, the underrated Ford Ranchero, which debuted two years before the El Camino, but never quite caught the zeitgeist like its Chevy rival. But one model the aforementioned car meet dude may forget to mention is the GMC Sprint. Similar to the El Camino in many physical ways, the Sprint is rarer, just as powerful, and, whisper it, will cost you half the price for the same spec. The GMC Sprint Is The Forgotten El Camino Bring A TrailerGMC is a heavy-duty brand, specializing in trucks and stuff where you probably wear gloves and a hat. By the start of the '70s, the Ford Ranchero was in its fifth generation, and the El Camino in its third, and the bean counters at GM probably realized that GMC should be cashing in on the coupe utility market. It was decided that GMC would launch one of these two-door car-like pickups, but there was one problem — GMC didn't really have a car to base it on.The solution was simple: base the new model directly on the existing Chevrolet El Camino. The result was the GMC Sprint, which shared its body, chassis, and mechanicals with its Chevrolet sibling. That meant a familiar range of powerplants, including 250ci inline-six engines and small-block 307 and 350ci V8s, with buyers also able to step up to big-block V8 power. At the top of the lineup sat the Sprint SP, which could be optioned with a 454-cubic-inch V8, effectively mirroring the top-end El Camino SS, but badged the Sprint SP. The GMC Sprint Had Muscle Car Pace Bring A TrailerUnsurprisingly, the GMC Sprint SP had enough punch to seriously trouble muscle cars of the era. The GMC Sprint was introduced for 1971, with the SP version available with a LS5 454, rated at 365 horsepower and 465 lb-ft of torque. The big block was mated to a GM Turbo Hydramatic 400 3-speed auto. The sprint to 60 mph was around 6.5 seconds, and the quarter mile would have been around the same as the feisty El Camino SS, which had been tested at 14.7 seconds, according to Hemmings.There are some Dodge Chargers that would be smoked by a GMC Sprint. An independent test of Chargers for 1971 showed the Charger SE reached 60 mph in seven seconds, when fitted with the 370-horsepower 440 Magnum, and achieved a quarter-mile in 14.93 seconds at 96.4 mph. A Charger Super Bee with the 385-horsepower 440 managed 60 mph in 6.9 seconds and a quarter-mile in 14.74 seconds at 97.3 mph. Why The GMC Sprint Arrived At The Worst Time Bring A TrailerWhile the popular El Camino was showing that there was a market for niche muscular utility coupes, the GMC Sprint couldn't have arrived at a worse time. While the Sprint SP version had been advertised with the availability of a 425-horsepower LS6 454, when it arrived in 1971 with reduced compression ratios, the LS5 454 was down to 365 horses.Emissions targets and a looming oil crisis meant that this was down to 270 net horsepower in 1972 for the Sprint SP, with 245 horsepower on the menu for 1973. In short, the big block GMC hero arrived at the end of the muscle car era, when most manufacturers were packing up and leaving altogether. This left the Sprint as a rare anomaly too; a forgotten chapter in the company's history. But 50 years on, this means that they are also a secret big block bargain. The GMC Sprint Is A Secret Bargain In The Muscle Car World Bring A TrailerOften, the word "rarity" equates to high demand and high prices — but not for the GMC Sprint. Throughout its lifespan from 1971 to 1977, the Sprint remained incredibly rare, especially when compared to its El Camino. GMC made around 7,000 Sprints a year, with fewer than 6,000 units in 1977, according to Hemmings. That year, Chevy produced 54,000 El Caminos. In 1971, Chevy managed to sell 57,000 El Caminos, according to Hagerty. The 454 Sprint SPs Are Among Some Of The Rarest Muscle Machines Out There Bring A Trailer The Sprint SP versions are particularly rare, with Hemmings reporting that only 249 SP Sprints were built in 1971, with some estimates saying that just 25 were built with the 454 LS5 engine. But here's the thing: a 1971 Chevrolet El Camino SS with a 454 mill will cost $56,100 in good condition, according to Hagerty's Valuation Tools. The rarer but almost identical 1971 GMC Sprint SP, also with an LS5, will cost $22,800. So less than half the price. However, the only problem seems to be actually finding one for sale. There Are Further Bargains To Be Had In The World Of Sprints And El Caminos Bring A Trailer If you are prepared to go for a slightly later 454 Sprint, when power figures had been drastically cut, there are even bigger bargains to be found. A 1974 GMC Sprint fitted with a 454 that pushes out 235 horsepower will cost $12,800 in good condition, says Hagerty, while a 1975 454 is down to just $12,500 (with output at the same 235 horsepower). At this point, the El Camino comes in at the same price for the same spec — $12,500 with a downtuned 235-horsepower 454. A 1978 Chevrolet El Camino with a 305 V8 costs $9,200.The El Camino continued into the '80s, long after the Sprint disappeared. Here you will find unbelievable bargains if you want the bragging rights of owning an El Camino, without any of the real kudos. An '84 El Camino with a six-pot motor will cost just $5,600. But you won't be winning many drag races for that money.Sources: Hagerty.com; Hemmings.com