A while back, we ran a post showcasing The Top 10 Most Underrated Engines of All Time based on responses from Summit Racing’s Facebook and Instagram pages.

This time around, the Summit Racing team flipped the script, asking simply:

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“The greatest high performance engine of all time is _______.”

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And surprise, surprise, over 1,000 people chimed-in with their thoughts. We collected the reader contributions and built a Top 10 list based on that feedback—here’s what we came up with.

Please note, sometimes folks gave us a specific engine, others gave the entire engine family, so we made some necessary compromises.

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10. American Motors AMX 390/Tall-Deck 390

The AMC Rebel Machine boasts one of the later tall-deck AMC 390 engines. (Image/OnAllCylinders)

Fun fact, there are actually two distinct types of the AMC 390. The first appeared as the short-deck version of the second-generation AMC V8 and used in AMC’s new Corvette fighter, the AMX. It was made for 1968 and 1969, before being replaced by the third-gen “tall-deck” 390 in 1970. The latter 390 only lasted for one year, as it was punched out to 401 cubic inches for 1971. In addition to being found in the AMX, you could get an AMC 390 under the hood of cars like the Javelin and Rebel Machine.

amc 390 engine with the go package
This particular 390 also has the fabled “Go Package” hop-up kit offered by AMC. (Image/OnAllCylinders)

Scott C. was the first one to call out the AMC 390 as “my choice, hands down!” And Peter M. concurred, saying “The 390 is a very underrated engine.” Burton W. spread some AMC love around by suggesting the aforementioned AMC 401 too.

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9. Rolls-Royce Merlin

(Image/Public Domain)

Look, Summit Racing didn’t specify that it had to be an automobile engine here, so we were happy to see folks like Rod T. submit the Merlin for consideration. Though it’s largely remembered for powering warbirds, Nick W. reminds us that it was used in trophy-winning race planes too.

Mike D. chimed in with “Great plane engine, but sadly doesn’t fit in most cars though.” Yet another commenter, Roger P. was quick to point out that “Yeah it does, you just need a little imagination, some skill, and some tools.”

The rules didn’t say anything about the engine being inside a car. (Image/OnAllCylinders – Alan Sakalas)

Developed by Rolls-Royce, the Merlin was also built under license by Packard here in the United States, and would go on to power some of the Allies’ most formidable fighters during World War II, namely the P-51 Mustang and Supermarine Spitfire. You can learn more about the engine here: The Merlin: How Rolls-Royce Teamed up with Packard to Help End World War 2

Runner-Up? A few folks brought up the Pratt & Whitney J58 engines that propelled the incredible SR-71 Blackbird. But we figured the Merlin would be a tad easier to stuff into a street car. Maybe.

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8. Chevy DZ 302 Small Block

(Image/OnAllCylinders)

When Chevy wanted to take its new Camaro racing in the Trans Am series, it needed an engine that would slip under the SCCA’s 305 cubic inch displacement cap. So, engineers went to the Chevy parts bin, took the crankshaft from a 283 small block and shoved it into a 327. The three inch stroke and four inch bore worked out to a tidy 302 cubic inches—and the legendary Camaro Z/28 302 was born. Rated by Chevy at “just” 290 horsepower, thanks to a hot cam and and other key upgrades, the powerplant actually made closer to 400. It was short-lived fun though, as the 302 was replaced by the LT-1 350 in 1970, as the Camaro entered its second generation.

chevy dz 302 small block engine in a camaro z 28
Confusing Ford fans since 1967! (Image/OnAllCylinders)

For a bit more qualitative analysis, Paul D. explains that “the DZ was a beast,” while Kimmo P. simply states “the SBC 302 rocks.” At the very least, Jose A. says “the overlooked Chevy 302 was something unique” and David S. calls it a “great option.”

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7. Ford 351 Cleveland

A Cleveland topped with Trick Flow Cylinder Heads helped propel this Mercury Cyclone Spoiler II to over 170 mph. (Image/OnAllCylinders)

Completely distinct from the 351 Windsor, the 351 Cleveland was the go-to performance engine for many Ford faithful throughout the 1970s and 80s, before the aftermarket caught up with quality performance upgrade parts for the 351W.

Not sure of the distinction? Read this: What’s the Difference Between a Ford 351 Windsor, Cleveland, or Modified Engine?

Though it only appeared on American shores from 1970-74, it remained in production in Australia for well over a decade, helping cement its status as a competitive powerplant.

Hmmmm…what engine did DeTomaso originally use in its jaw-dropping Pantera? (Image/OnAllCylinders)

Interestingly, the 351C is when we started seeing folks dissect the nature of Summit Racing’s original question, as Allan P. describes. “Well, you need to elaborate, are we talking about only using OEM parts? If so, the Ford 351 4V Cleveland.”

But plenty of others were a bit more direct.

“The 351 Cleveland was indestructible. It could take whatever you threw at it,” says Mike A. Following a similar sentiment, Ryan E. adds “look what Bob Glidden was able to accomplish with it.”

And Hickory W. offers a further consideration. “If it ain’t the greatest, it sure is the prettiest-sounding one!”

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6. Chevy 350 (Family)

Perhaps the peak of classic SBC power came in the early 1968-72 C3 Corvettes, where several iterations made north of 300 (gross) horsepower. But the new LT1 generation that began in 1992 saw a return to glory with the LT4 easily topping 330 hp (net). And let’s not forget the radically re-worked OHC LT5 found in the 1990-95 Corvette ZR-1. (Image/OnAllCylinders)

OK, this is where picking a specific engine gets tricky.

Beyond just saying “Small Block Chevy,” plenty of folks suggested the ubiquitous Chevy 350. Yet many didn’t specify which fighting trim, so we opted to just generalize it all under the 350 umbrella. And that’s not surprising, because the 350 has been through a lot, appearing near the end of the 1960s musclecar heyday and soldering on in various forms until the arrival of the heralded LS series in 1997—which by the way, also bowed with a 350ci (5.7L) displacement LS1.

George Lyons built up an early-spec LT-1 350 using period-correct parts, then stuffed the whole thing into a C2 Corvette Sting Ray. (Image/George Lyons)

As with the Ford 351C above, the Chevy 350 caused some gearheads to ponder the overall nature of the question.

Remember Allan P. and his comment on the 351C? Well, he followed up with “If you talking about with all the aftermarket add-ons, then Chevy 350 will reign supreme.” And that sentiment was echoed by Richard D. with his comment “If most popular, then maybe the Small Block Chevy 350.”

Yet Jeff L. gives plenty of reasons why the 350 deserves a nod on the list, “Not the most horsepower or cubic inches, but all around interchangeable parts, low cost, reliable, and easy to work on.” Manon P. was a bit more generous with “the 350 Chevy has been put in every car ever made and most trucks.”

Perhaps T.J. summed it up best with “it’s about the most hot rodded engine ever and came in many different performance packages.”

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5. Pontiac 455 (HO & SD)

Stricter emissions requirements meant that 455 would fade away after 1976. (Image/OnAllCylinders)

Matthew L. came out swinging with his nomination of the mighty Pontiac 455. “Only Pontiac had the [guts] to release a high performance engine in the EPA era when all the other manufacturers were pulling their engines from the market.” Folks like Glenn F. agreed, and Ted F. alluded to another engine on this list in his comment, “a close toss up between the Pontiac Super Duty 455 and the Chevy LS6 454.”

We spotted a modified Tri-Power 455 stuffed under the hood of this gorgeous first-gen GTO. (Image/OnAllCylinders)

While several commenters just offered the Pontiac 455, a few included either the HO/High Output or SD/Super Duty designations. And that’s an important distinction to make, as the Poncho 455 came in a few flavors. The 455 HO showed up in 1970 and at its peak, made around 360-370 (gross) horsepower, depending on the vehicle. Conversely, the 455 SD arrived for the 1973 model year, and emissions compliance meant that it was cranking out 290 horsepower (net).

Yet after its retirement in 1976, many credit the 455 as being the last of the “big” power engines stemming from Detroit’s horsepower wars of the late 1960s.

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4. Chevy Big Block (Family)

“The LS6 454/450 hp was the king of the hill for a long time.” – Rob O. (Image/OnAllCylinders)

Remember the Chevy 350, when we said folks didn’t always spec out exactly which 350 they meant? Well, the same holds true for the Chevy Mark IV Big Block.

In fact, there wasn’t much of a distinction made among the commenters between the W-Series Big Block that begat the 409 and the later Mark IV Big Block that found fame in the late 1960s musclecar heydey. “The BBC will make the most power normally aspirated. Total pro stock domination over the years,” explains Randy F.  

Originally only found in the Corvette, savvy buyers could later check the 427/425 hp L-72 COPO option for their Chevelle or Camaro. (Image/OnAllCylinders)

There was no shortage of specifics though, and we heard some familiar alphanumeric RPO codes

“Hard to be a [427] Chevy L-88,” claims Skip P., which led Rob R. to support that by simply saying “The L-88 was a beast!” Continuing the 427 train, Eric D. offered his take on the uber-rare ZL-1. “A beautiful whittled down chunk of aluminum.” David D. concurs, adding “427 Chevy. Awesome motor.”

Not to be overlooked, Harold R. quickly added “454 LS7 Chevy big block” to the discussion.

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3. GM LS (Family)

The first LS was the 5.7L LS1, which debuted in the Corvette in 1997 and later migrated to a few other GM performance cars—including the gone-too-soon Pontiac GTO. (Image/OnAllCylinders)

Just like the Chevy 350 and Big Block listed above, quite a few commenters just chimed in with “the GM LS.”

Problem is, the GM LS family includes an massive line of distinct engines, ranging from the front-wheel drive 5.3L LS4 to the naturally-aspirated glory of the 500+ HP 7.0L LS7. So while we would’ve loved to narrow it down to a single powerplant, we decided to lump all the LS engines together.

“Has to be the LS family,” says Robert G. “So many options and possibilities, from high-boost drag monster to short-stroke road course king.” Robert R. continued with “reliability, versatility, and unlimited potential.”

Its compact size and robust aftermarket support means the LS is a popular candidate for swaps and restomods, as evidenced in this LS6 found in a 1952 Chevy Suburban. Putting on a set of custom valve cover adapters to mask the coil packs even gives it a throwback SBC aesthetic. (Image/Summit Racing)

But just because we’ve got the LS as a single entry doesn’t mean gearheads didn’t offer up some specifics, either.

“LS9, the possibilities are endless,” says Paul W. Then, Ben H. gives his nod to the LS6/LS7. “They’re light, make great power stock, are easily upgraded, and the dry(ish) sump design make them perfect for off-roading and road racing.”

Allen E. closes with “LS family all day. Even if you don’t like Chevy you have to admit how great these engines are.”

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2. Chrysler/Mopar 426 Hemi

426 Street Hemi engine in a 1966 Plymouth Satellite
(Image/OnAllCylinders)

Yeah, honestly, when it came to our list, the order was first, then second…and then everybody else. That said, coming it at number two is the only engine that has its own nickname, became its own buzzword and, begat an entire marketing campaign.

“That thing got a Hemi?” is as relevant today as it was when the Elephant engine first rumbled out of Detroit. Finding a 426 under the hood of, say, a Barracuda or Charger immediately jumps the value through the roof and its signature exhaust burble is music to every gearhead’s ears.

If the factory-rated 425 horsepower isn’t enough, you can always do…things. (Image/Summit Racing)

Here’s just a sample of what folks said:

  • “Even as a Ford guy, I have to go with the Hemi. There’s really nothing that comes close.” – Louis L.
  • “The 426 Hemi was damn near unbeatable during the 1960s.” – Richard L.
  • “Nobody in any upper drag racing class is using Chevys and Fords. And all those Pro Mods jumped ship and switched to Hemis.” – Pete F.
  • “Hemi’s been the foundation of the highest HP engines for decades.” – Byron M.
  • “It is all subjective, although only one engine has their own class in the NHRA S/S class…” – Brian B.
  • “The real motor with the spark plugs in the middle of the valve covers.” – Michael V.A.

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1. Ford 427 SOHC “Cammer”

(Image/OnAllCylinders – Dave Fuller)

Behold the engine that pushed the Mopar 426 Hemi from the top spot.

Nicknamed the “Cammer,” the engine is basically a 427 Ford FE block with a single overhead cam placed in each cylinder head, driven by a six-foot long timing chain weaving its way around the front of the engine.

About half the comments alluded to the fact that Ford’s “Cammer” was banned from NASCAR competition, which ignited a lot of discussion as to why. While the circumstances around the ban aren’t as cut-and-dry as some folks think, it’s essentially true. Kept off the NASCAR Speedways, the OHC Ford 427 achieved its legendary reputation elsewhere, namely in NHRA competition alongside names like Kalitta and Prudhomme.

It seems there was some name confusion regarding the Ford 427 FE engines as well. The 427 SOHC Cammer was a Side-Oiler, but as you can see here, not all Ford 427 Side-Oilers were Cammers. We’d still welcome any of them in our engine bay though. (Image/Jim Smart)

Just like the Hemi above, we’ll simply list some of the Cammer comments from the Ford faithful:

  • “Clearly the 427 Cammer engine.” – Ryan G.
  • “The Ford FE is the best of all time, since it includes the 427 SOHC & 427 side oiler.” – Doug D.
  • “Banned by NASCAR because it was too much!” – Robert S.
  • “Chrysler did not want to compete against that engine.” – Norman T.
  • “Not a Ford guy, but the 427 “Cammer” was quite a build.” – David J.
  • “The OHC 427 could have very easily been the best engine. It was decades ahead of others.” – Chuck H.
  • “The Ford 427 SOHC, which was 660 hp, right out of the crate.” – Jeff D.
  • “Ford’s FE (specifically the 427) is the greatest by its range of success. It won at LeMans, Pikes Peak, NASCAR, USAC, NHRA, SCCA, and more.” – Cody S.
  • “Looks like the 427 Ford is the correct answer.” – Bennie E.

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Honorable Mentions

We couldn’t cap this list at 10, so here are a few other nominations that deserved a shout-out.

  • “Saturn V” – Shad S.
  • “The overbuilt 2JZ from Toyota and Honda’s K20.” – Ryan D.
  • “Toyota 2AZ-FE. 4 cylinders of Camry and Tarago fury.” – Michael J.
  • “Ford DFV, competed in Formula 1 for 16 years.” – Michael F.
  • “The Aussie Ford Barra 6-Pack.” – Rusty C.
  • “Ford Godzilla engine!” – Rod G.
  • “Ferrari Tipo 053 3.0L” – Jon M.
  • “The Buick 455 Stage 1” – Richard H.
  • “Ford Cosworth” – Gary H.
  • “Ford 6.7L PowerStroke” – Brady S.

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Disagree with the list? Let us hear about it in the comments section below!