Want a not-so-hot take? Not every iconic American muscle car came with the engine it deserved. Whether it was born in the wrong era or the engineers just didn’t care to make the right moves, plenty of amazing machines were robbed of their true potential. That got the crew here thinking, what if things were different? What if the greatest American cars were paired with the greatest engines? That’s not exactly a wild, new thought, but we do have the HotCars engine calculator to help us gather the data.What makes the HotCars engine swap tool so interesting is that it’s not perfect. It doesn’t tell us how a car will perform in ideal conditions. It tells us what will hold it back, and what real-world performance may actually look like because of it. That said, we used it to see what would really happen if you took ten of the most iconic American cars of all time and gave them the best engines available from various points in time. While the results are awesome in almost every case, they might not exactly be what you’re expecting. 1955 Ford Thunderbird Coyote Swap 1/4-Mile Time: 14.55 Seconds MecumThe Ford Thunderbird is one of the greatest cars produced by the Blue Oval that just technically squeaks into the muscle car category. It’s more widely known as a personal luxury car than an all-out performance tyrant but it did have a V8 under the hood that performance junkies have always tweaked with. We wanted to see what the original 1955 model with something a little more modern and a whole lot meaner under the hood.HotCars The baddest 1955 Ford Thunderbird was rolling with a 198-horsepower V8. As good as it was for the time, a Coyote 5.0 making 486 horsepower and 420 lb-ft of torque makes the old ‘Bird a whole lot better. With Ford’s favorite modular engine, the Thunderbird would move from 0-60 in 5.19 seconds and clear the quarter-mile in 14.55 seconds. Surely, someone at Ford is thinking about making this happen with the right tires and suspension to get even better performance out of it. 1987 Buick Grand National Stage 1 GSX Swap 1/4-Mile Time: 12.23 Seconds Mecum AuctionsNobody ever said the Buick GNX is underpowered. These turbocharged V6 monsters redefined the muscle car segment by showing the true potential of smaller engines with forced induction. Still, many people wished the iconic, menacing black bodies were paired with a legendary V8 engine. So, we thought, what if Buick’s most notorious big block was used instead of the 3.8-liter wonder?HotCarsA Buick Grand National GNX with a Stage 1 GSX engine under the hood is something everyone would love to see. The monstrous V8 would bump power up from the original 276 horsepower rating to 360 horsepower. Torque would also take a massive leap from 360 lb-ft to a whopping 510 lb-ft. Even if the engine weighs more, this is enough to cut the 0-60 time down from 4.7 seconds to 4.3 seconds and the quarter-mile time down from 13.4 seconds to 12.23 seconds. We won’t argue over which version is cooler, though, because you just can’t go wrong with a GNX. 2016 Challenger SRT 10 Viper Swap 1/4-Mile Time: 11.96 Seconds DodgeThe last wave of Dodge Challengers did anything but disappoint the vast majority of muscle car fans. But, despite offering world-record performance stats, there are people who argue it could have been better with a Viper V10 engine under the hood. Would it really? We punched the combination into our calculator to find out.HotCars We decided to use a2017 Viper ACR’s V10 for our test. This 8.4-liter tyrant is producing a whopping 645 horsepower and 600 lb-ft of torque. It’s got enough juice to sling the Challenger from 0 to 60 mph in 4 seconds and clear the quarter-mile in 11.96 seconds. While the Hellcat has it beat, this might actually have been an extremely cool factory offering from Dodge. Though we ultimately understand the lack of motivation to make it happen. The Hemi is just too good. 1969 Dodge Charger Daytona Hellcat Redeye Swap 1/4-Mile Time: 11.58 Seconds MecumThe 1969 Dodge Charger Daytona was robbed of its true potential. These cars were forged in wind tunnels to dominate NASCAR, which they did. Unfortunately, a rule change effectively stopped them from racing in their original form. The sad part is that they were just getting started, and there’s no telling what could have been.HotCarsWe wanted to know what a ‘69 Daytona would perform like with a Hellcat Redeye engine under the hood, the spiritual successor to the legendary 426 that still wears the crown of being king of the big blocks. The blown third-gen Hemi is producing 797 horsepower and 707 lb-ft of torque. This will sling the winged beast from 0 to 60 mph in 4.26 seconds (imagine that) and through the quarter-mile in 11.58 seconds. As solid as those numbers are, the real question is, how will it perform at 200+ mph? 1964 Ford Mustang LTD Swap 1/4-Mile Time: 11.53 Seconds Via: Bring a trailerThe original Ford Mustang got a lot of things right. Birthing the Pony car segment would define an entire generation, eventually leading to ground-breaking machines that push the very laws of physics to their breaking point. Turns out a featherweight platform with a strong engine is something the whole world loves. What if you took the best of today’s Mustangs and crammed them into the original body?HotCarsThe Mustang GTD is an amazing machine that is redefining what the world thinks of American cars. If you took its guts and swapped them into a 1964 model, you would end up with something even more ridiculous. The 5.2-liter Predator V8 makes 815 horsepower and 664 lb-ft of torque, which the original 289 couldn’t hold a candle to. This cuts the 0-60 time down from 7.5 seconds to 5.12 seconds and the quarter-mile time from 15.2 seconds to 11.53 seconds. Even with the wrong tires, that’s damn fast. 1970 Nova LT5 Swap 1/4-Mile Time: 11.34 Seconds MecumThe Nova has long been the favored platform among mad scientists. Criminally insane speed freaks like Don Yenko have been stuffing fire-breathing V8s into the compact muscle car since the dawn of time. The meanest coming from Chevrolet had a 396 big block under the hood. It can be even more insane, though, especially with GM’s wildest modern naturally-aspirated V8 on the table now.HotCarsStuffing an LT5 V8 into a 1970 Nova SS is every bit as amazing as you think it’d be. Not only does it shave some weight, but it bumps power up significantly. The 755-horsepower LT5 makes more than double the power of the original 396 and 715lb-ft of torque. This would propel the Nova from 0 to 60 mph in 4.27 seconds and through the quarter-mile in 11.34 seconds. Yes. Someone needs to start working on it right away. 2026 Dodge Charger Hellcat Swap 1/4-Mile Time: 11.31 Seconds Jared SolomonThe greatest crime of modern times was when Dodge robbed the 2026 Dodge Charger of a Hellcat engine. While the Sixpack engines are great, they don’t have squat on the legendary supercharged V8 engine that’s made Mopar what it is today. And with the TRX bringing it back in a more powerful than ever package, everyone wants to know what the Charger could do with the V8 it deserves.HotCarsI wrote an entire article on this that you should check out, but the short version is that the new 777-horsepower Hellcat V8 is a major improvement in all fields. The 0-60 time is a blisteringly quick 3.41 seconds, and the quarter-mile time is 11.31 seconds. Not only is this better than Sixpack H.O. motors, but it’s outrunning the more powerful EV variant that sits on top of the performance roster. Dodge needs to just do it already. 2017 Ford Mustang Ford GT 3.5 Ecoboost Swap 1/4-Mile Time: 11.21 Seconds Bring A TrailerThe 2017 Mustang is anything but a slouch. With a 5.0 V8 making 435 horsepower and 400 lb-ft under the hood, these cars are solid performers. However, much like the Challenger, existing alongside a supercar from the same brand always had people wondering if the Mustang could have been even better.HotCarsThe Ford GT was briefly revived in 2017 with a 3.5-liter EcoBoost V6 as the engine of choice. While it had two fewer cylinders than the Mustang GT of the same year, it was much more powerful. Swapping the 647-horsepower six-cylinder into the Mustang makes some substantial improvements. A 3.77-second 0-60 time and 11.21 quarter-mile time are nothing to scoff at. However, the 5.2-liter Predator engine with a blower on top was worth the wait. 1986 Pontiac Fiero LT7 Swap 1/4-Mile Time: 9.45 Seconds via KBB.comLet's be honest, the Fiero isn't exactly a rocket-ship, even though it looks like one. Fun? Absolutely. Don’t get us wrong, the mid-engine wonder offered was respectable for its time. However, 140 horsepower just isn’t enough to get the job done today. To keep up with the times, you’ll need to swap in another, much more potent GM mid-engine masterpiece.HotCarsThe C8 Corvette is a straight-up supercar killer that’s commanding respect from all corners of the globe. Its LT7 belting out 1,064 horsepower would make a missile out of the Fiero. As you’d expect, the tires are the weakest link for this build, keeping numbers from their full potential. Still, a 0-60 time of 3.75 seconds and a quarter-mile time of 9.45 seconds will knock the smirk off anyone’s face who doubts it. L023 Dart Demon 170 Swap 1/4-Mile Time: 8.22 Seconds Mecum AuctionsThe LO23 Dart is among the most legendary Mopar muscle cars of all time. It’s proof that engineers at big carmakers are no different than typical hot rodders. Like many of us, they set out to see what would happen if you slammed the most powerful engine into the smallest possible car. The result was a 426-Hemi-powered Dart that could cut through the quarter-mile in 10 seconds.HotCarsWhat if the Hemi Dart were alive today? What if Dodge decided to slam a Demon 170 engine into one? Well, the results are even better. The 426 Hemi has plenty of potential, but a 1,025-horsepower 6.2-liter Demon engine is a lot stronger out of the box. This crazed V8 would send the 1968 Dodge Dart from 0 to 60 mph in just 2.61 seconds and clear the quarter-mile in 8.22 seconds. With this combo, not even the mighty ZR1X is keeping up in a straight line.
