A Builder Put an LS, a Hemi, and a Coyote in the Same Plymouth Duster — Only One Engine Won the Crown

One early-’70s Plymouth Duster ran three different V8s in a single year just to settle the ultimate garage argument. Here’s which swap engine actually came out on top — and why the runner-up might still be the smarter buy.

Every muscle car garage eventually has the same argument: LS, Hemi, or Coyote — which V8 is actually the best engine to drop into a classic? Most builders pick a side and never test the other two. One builder decided to settle it for real. He took a single early-1970s Plymouth Duster that hadn’t turned a wheel in decades and ran it through three different engines in the same year, matching each swap to the make it was built to prove. The car crossed the finish line at over 100 mph more than once, and by the end, the results weren’t close. If you’ve ever argued about which engine belongs under your hood, this is the closest thing to an actual answer.

The Build That Turned a Garage Debate Into an Experiment

The video comes from The Questionable Garage, a channel built around exactly this kind of hands-on comparison. Builder Jared Pink used his beat-up Duster to chase what Holley calls a “Triple Crown” — running the same car at all three of Holley’s signature Bowling Green, Kentucky events in a single season: LS Fest for GM power, MoParty for Mopar power, and Ford Fest for the Blue Oval faithful. The rule was simple and brutal: the engine had to match the event, so the Duster needed a different V8 swapped in for each one.

That meant pulling and reinstalling drivetrains on a tight turnaround — LS Fest and MoParty landed less than a week apart — and then standing on the throttle at the strip each time to see what the car could actually do. At LS Fest, Pink said the Duster was “shaking a little bit” as it crossed the traps at 114 mph. After living with all three engines in the same chassis, back to back, he ranks them: GM’s LS family first, the Mopar Gen III Hemi second, and Ford’s Coyote third — not because any of them is bad, but because of how each one behaves once it’s actually sitting in a 50-year-old engine bay.

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Why a Plymouth Duster Was the Perfect Guinea Pig

The choice of car mattered as much as the choice of engines. The Duster was Plymouth’s compact A-body coupe, built on the same small platform underpinning the Dodge Dart, and it earned a reputation in the early 1970s as one of the cheapest ways into real performance — a bargain alternative to the bigger, pricier B-body muscle cars like the Road Runner and the Charger. That small, light chassis and its notoriously tight engine bay are exactly why it makes such a brutal swap-comparison tool. Fitting a factory-correct small-block is one thing. Fitting three completely different V8 architectures — each with its own oil pan clearance, accessory layout, and transmission bellhousing pattern — into the same narrow Mopar shell, three times in one year, is the kind of stress test most builders never put themselves through voluntarily. A Mopar-badged car spending most of its season running GM and Ford power is also exactly the kind of cross-brand irony that gets die-hard “Mopar or no car” types talking in the comments, whether they admit it or not.

Why the LS Keeps Winning the Swap Wars

The numbers explain the verdict. GM’s LS family has been the default swap engine since the Gen III version debuted in the 1997 Corvette, and the used market is flooded with them as a result. A 5.3-liter LS truck engine can be found in salvage yards for as little as $600, and the factory 6.2-liter LS3 is rated at 430 horsepower and 424 lb-ft of torque right off a wrecked Camaro or truck — before anyone touches a wrench. Chevrolet Performance’s crate version of that same 6.2-liter, the LS376/480, is rated at 480 horsepower out of the box. None of that is the real advantage, though. The real advantage is that practically every part — wiring harnesses, motor mounts, swap kits, tuning software — already exists for nearly any car you’d want to put one in, down to conversion kits for vehicles as far from a muscle car as a Lexus or a Land Rover.

The Mopar Gen III Hemi tells a more complicated story. Chrysler brought it back in 2003 for trucks, and by 2005 the 5.7-liter version was making 345 to 350 horsepower in the Dodge Charger R/T, the Magnum R/T, and the Chrysler 300C. The larger 6.4-liter “392” variant bumped the bore and stroke up considerably for even more output. Mopar’s own crate engine kits make the swap more plug-and-play than it used to be — a tuned 5.7-liter kit is rated at 383 horsepower, and the 6.4-liter SRT crate engine runs right around $8,045 before installation. Early Gen III Hemis are also common and cheap in salvage yards, which is part of why Pink ranked the Hemi ahead of the Coyote — it splits the difference between LS-style affordability and factory-fresh power.

Ford’s Coyote came in third, and that’s a surprise to a lot of Blue Oval loyalists given how good the engine is on paper. The all-aluminum 5.0-liter debuted in the 2011 Mustang at 412 horsepower and climbed as high as 460 to 480 horsepower in later Mustang and F-150 applications, all with dual overhead cams and independently variable intake and exhaust timing — technology the LS and early Hemi simply don’t have. The catch is size and support. The Coyote is physically larger than an LS, which makes it tighter to shoehorn into a narrow engine bay like a first-generation Duster, and its aftermarket — while serious — still isn’t as deep or as cheap as the ecosystem built up around two decades of LS swaps.

What This Actually Means for Your Next Swap

None of this makes the Coyote a bad choice — it’s arguably the most advanced engine of the three, and viewers in the comments pointed out that a simple supercharger and the right oiling setup can put Coyote horsepower numbers well past what the same money gets you from an LS. The takeaway from running all three back-to-back in the same car isn’t that one engine is objectively superior. It’s that cost, parts availability, and how much custom fabrication you’re willing to do should drive the decision more than brand loyalty does. An LS swap is still the cheapest and easiest way into serious horsepower for almost any chassis. A Hemi swap gets you closer to factory-engineered simplicity, especially with a crate kit, if you’re willing to spend more. And a Coyote swap remains the technically newest and most sophisticated option — it just asks for more room, more budget, and more patience.

That’s the real value of watching someone actually do the experiment instead of just arguing about it online: the “best” engine depends entirely on what you’re optimizing for, and now there’s a 50-year-old Duster with the dyno sheets and track times to prove it.

It also explains why the brand-loyalty arguments in the comment section never really end. One commenter put it best: there are Ford guys, Chevy guys, and Mopar guys, and then there are just car guys — the ones who’ll run whatever engine actually gets the job done, regardless of what badge is bolted to the trunk lid. That’s the spirit the Triple Crown stunt was built on. Pink wasn’t trying to prove his Duster was a better Mopar, a better Chevy, or a better Ford. He was trying to find out which swap made the most sense for someone starting from zero, with a chassis that didn’t care what was bolted between the frame rails.

If you’re staring at your own project right now trying to decide, the short version holds up: start with what’s already cheap and plentiful near you. For most people in most parts of the country, that’s still an LS pulled from a wrecked truck or Camaro. If you’d rather stay inside the family and don’t mind spending a little more for a crate kit that bolts in cleanly, the Gen III Hemi is the compromise that keeps showing up in comment sections as the sentimental favorite. And if you’ve got the engine bay room and the budget for it, nobody’s going to tell you the Coyote was the wrong call — it just asks for more of both before it pays you back.

Watch the full video above and let us know your thoughts in the comments.