10 Weirdest GM Muscle Cars You’ve Probably Never Heard Of
When you think of GM muscle cars, names like the Chevelle SS, Pontiac GTO, and Camaro Z28 probably come to mind. But General Motors didn’t just build icons—they also experimented with some seriously strange, rare, and downright bizarre muscle machines over the years.
From cars that looked like they belonged in a sci-fi movie to muscle-bound beasts that never got the recognition they deserved, GM’s history is filled with forgotten oddities. So, let’s take a look at 10 of the weirdest GM muscle cars you’ve probably never heard of.
1. 1977 Pontiac Can Am
Pontiac had big plans for the Can Am, a high-performance version of the LeMans with a shaker hood, 6.6L V8, and bold racing stripes. It was supposed to be the next muscle car hit—but after just 1,377 units were built, a broken mold (literally) stopped production.
This Pontiac was powerful, rare, and wrapped in ‘70s excess—yet it vanished almost as quickly as it appeared.
2. 1969 Chevrolet Camaro ZL1
A Camaro with a Corvette’s all-aluminum 427 V8? Sounds like a dream, but it actually happened. Chevy built just 69 ZL1 Camaros, making it one of the rarest muscle cars ever.
With over 500 horsepower, it was brutally fast—but also absurdly expensive, which is why most people have never even seen one.
Today, they sell for millions, making this one of the weirdest (and most valuable) Camaros in history.
3. 1973 Chevrolet Chevelle Laguna 454
Chevy’s Laguna Type S-3 wasn’t your typical muscle car—it looked more like a grand touring coupe. But under the hood, you could get a massive 454 cubic-inch V8, making it a true powerhouse.
Its aerodynamics were so good that NASCAR teams loved it, and it performed strongly on the track. Unfortunately, its odd styling and rising gas prices meant it never became a household name.
4. 1989 Pontiac Turbo Trans Am
The 1989 Turbo Trans Am was a sleeper legend. Instead of a V8, it packed the same turbocharged V6 from the Buick Grand National, making it faster than even the mighty Corvette of the same year.
It was the official pace car of the Indy 500, but most people had no idea Pontiac built a turbocharged Trans Am that could outrun nearly everything on the road.
5. 1971 GMC Sprint SP
You’ve heard of the Chevy El Camino, but what about its GMC twin, the Sprint SP? This was GM’s attempt to sell a muscle truck under the GMC brand, complete with an optional 454 V8.
Despite being just as powerful as the El Camino SS, the Sprint SP faded into obscurity. Today, it’s an ultra-rare relic of GMC’s brief muscle car experiment.
6. 1970 Buick GSX Stage 1
Buick isn’t the first name that comes to mind when you think of muscle cars, but the GSX Stage 1 was a certified beast. With a 455 cubic-inch V8 and absurd amounts of torque, it could outmuscle most Chevys and Pontiacs.
Yet, Buick’s reputation for making “old man cars” kept it from getting the recognition it deserved. Only a few were built, making this one of the most bizarre sleepers of the muscle car era.
7. 1966 Oldsmobile Toronado
Muscle cars are supposed to be rear-wheel drive, right? Well, Oldsmobile didn’t get the memo when they built the Toronado, a front-wheel-drive muscle car packing a massive 425 V8 with 385 horsepower.
It looked like a spaceship and handled like a tank, but its weird drivetrain setup kept it from becoming a true legend. Still, it was one of GM’s boldest muscle car experiments.
8. 1975 Chevrolet Monza Mirage
With gas prices soaring in the mid-‘70s, GM tried to shrink the muscle car formula into something more fuel-efficient. Enter the Monza Mirage, a lightweight coupe with bold racing stripes and a rare, dealer-installed 5.7L V8.
It looked like a race car but had the underpinnings of a tiny economy car, making it one of GM’s strangest attempts at a performance machine.
9. 1968 Oldsmobile 4-4-2 W-31
Oldsmobile took their already-potent 4-4-2 and turned it into something truly bizarre with the W-31 package. This wasn’t your average muscle car—it came with a ‘Ram Rod’ induction system, a 350 cubic-inch V8 pumping out an underrated 325 horsepower, and a lightweight setup meant for drag strips.
Most buyers didn’t even know it existed because Olds buried it in fine print, and only a handful were ever built. It was a secret weapon that could embarrass bigger engines, but its obscurity makes it one of GM’s strangest muscle car footnotes.
10. 1977 Pontiac Astre Formula
Pontiac tried to bring muscle car styling to a subcompact with the Astre Formula, which looked like a shrunken-down Firebird. It had hood scoops, racing stripes, and all the visual cues of a muscle car—but its tiny engine meant it had no muscle at all.
It was an odd mix of performance looks with economy car power, making it one of GM’s strangest muscle car misfires.