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Milestone Muscle Car Engines

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by Barry Kluczyk  More from Author

We examine 12 power plants that delivered big performance and influence

Literally and figuratively, the heart of the muscle car era was the iron-block, overhead-valve V-8. Every manufacturer had its own – and in most cases, more than one. Small-blocks, big-blocks, solid-lifters, three deuces and dual quads competed for enthusiasts’ attention and paychecks.

Of course, other factors contributed to a muscle car’s market success, but the motivating factor behind all the greats was their engine. And surprisingly, it didn’t have to be the most powerful to make an impact. If that were the case, the Chevy LS6 454 and earlier COPO 427 engines would be at the top of the heap and that would be it. It’s the 500 lb.-ft. of torque of the Buick 455 and the high-winding capability of Ford’s Boss 302 that made them competitive.

We’ve put together a roster of engines that left indelible and historical marks on the history of the American muscle car. As noted above, it’s not merely a ranking of the most powerful, but a look at the most important power plants and how they contributed to their respective brands’ street credibility and, in the decades since, their mythology.

Brand loyalties being what they are, we’re sure no two enthusiasts will agree with all of our selections. Drop us a line at askbrian@autotrader.com and let us know which engines you feel were snubbed. And by the way: our list isn’t ranked with a winner. It is simply a collection of the engines determined to be the most noteworthy of the muscle car era.

Let the bench racing begin.

 

 

OLDSMOBILE 371 J-2 GOLDEN ROCKET

It’s rarely mentioned as a performance pioneer, but the 1957 Oldsmobile 371 “J-2” Golden Rocket engine deserves more respect. The early Olds V-8 was an overhead-valve (OHV) design that was very similar to the Cadillac and Chevy V-8s. The Chevy had the edge on cylinder-head airflow, but the Olds made up for it with cubic inches.

With its J-2 triple-carb induction system, the 371 was rated at 300 horsepower and 400 lb.-ft. of torque – 17 horses more than the much-celebrated-yet-finicky 283-horse, fuel-injected Chevy 283 engine.

The big-inch Olds topped the output of the non-Hemi Mopar 318 engine (290 hp) and Ford’s 312 (245 hp). And when it came to its GM-engine cousins, the J-2 engine equaled the output of Buick’s top 364-cid Nailhead engine and bested Pontiac’s top 347-inch, Tri-Power engine (290 hp).

Indeed, in that cloud of swirling exhaust gases gathering before the Big Bang of the muscle car era, the J-2 was one of the catalysts. They’re rare sights today and the Super 88 models they powered weren’t the fastest cars ever built, but the contribution of the J-2 cannot be denied. 

 

 

CHEVROLET 409

Born in 1958, Chevrolet complemented its landmark small-block with the larger “W”-series engines – so-named because of its W-shaped heads/valve covers. Their unique feature was that the combustion chamber was located in the upper part of the cylinder, not the head. This was achieved by combining a cylinder head deck that wasn’t perpendicular to the bores and matched with crowned pistons. The design enabled a wedge-shaped combustion chamber, with the goal building a broad torque curve that started at low rpm. 

The W engine was born with a 348-cu.-in. displacement, but grew to 409 cubes in 1961. It became an early muscle car engine when it was matched with the ’61 Impala SS, where it was rated at 360 horsepower. Output grew to 380 horsepower in 1962, using a single Carter AFB carburetor and it became a cultural legend when the optional 409-hp edition was released. It used an aluminum intake to hold a pair of four-barrel carbs, delivering the magical 1 horsepower per cubic inch. The 409 mopped up the Super Stock ranks and was immortalized in the famous Beach Boys song.

Besides its cultural impact on the early days of the muscle car wars, the W-series engine and its 409 variants paved the way for the Chevy big-block engine that would dominate later in the Sixties.

 

CHRYSLER 426 MAX WEDGE

In a Dodge it was the Ramcharger and in a Plymouth it was the Super Stock, but the core 426-cubic-inch Max Wedge engine was the same. Introduced for 1963, it was Mopar’s weapon in the escalating Super Stock drag racing wars, which was pushing larger, more powerful engines into stripped-down production models built to be as light as possible. And just like the 409 was immortalized in song, so was this engine, as it was the power behind the “Little Old Lady from Pasadena.”

The engine was based on the Mopar 413 engine with torque-building wedge combustion chambers, but bored out to displace 426 cubic inches. Dual Carter four-barrels fed the engine. They were diagonally opposed on a large, wide intake manifold with long intake runners designed to build high-rpm horsepower on the drag strip. The engine also featured unique, upswept ram’s head-style exhaust headers. Two versions were available, one with 11.0:1 compression that was rated at 415 horsepower and another with a thumping 13.5:1 compression that created 425 horsepower.

Later, a Stage III 425-hp version arrived, packing lower, 12.5:1 compression, larger-bore carbs and new head castings, but still rated at 425 horses.

 

FORD FE 427

Ford’s FE engine family debuted in 1958. It was a Y-block design, meaning the cylinder block skirts extended below the crankshaft centerline. It was originally developed as a bread-and-butter engine, with some versions designed for low-rpm work as truck engines. As the performance war of the early-Sixties grew to include battles on drag strips and NASCAR super-speedways, the FE was drafted to fight on both fronts.

The 427 version of the FE was introduced in 1963 as a racing engine (and it truly only displaced 425 cubic inches), although it found its way into low-volume production models for homologation purposes and, eventually, into more conventional production cars. Its cast iron block had a thicker deck to support higher compression, while the cylinders were cast using cloverleaf molds, meaning the corners were thicker all down the wall of each cylinder. Many 427s used a steel crankshaft and most used solid valve lifters, although the ’68 block was designed for hydraulic lifters.  

Two distinct versions of the 427 block were produced: Top-oiler and side-oiler. The top-oiler version was the earlier, and delivered oil to the cam and valvetrain first and then the crankshaft, while the side-oiler block, introduced in 1965, first sent oil to the crank. Ford also produced tunnel-port heads for the 427. They enhanced airflow by running the pushrods through the intake ports, which eliminated the restriction imposed by squeezing the intake ports between the pushrods.

 

PONTIAC 421 SUPER DUTY

Introduced in 1961 as a dealer-installed package, the 421 Super Duty engine was a factory-engineered racing engine. Like high-output mills from Chevy, Mopar and Ford, the Pontiac Super Duty was developed to help racers win on the drag strip and stock-car circuit, with the civilian-sold units the requirement for sanctioning-body legality. And while it started as an over-the-counter product, Pontiac began offering factory-installed Super Duty engines in 1962, where it was offered with a single four-barrel or 3x2 induction.  

The Super Duty returned in ’63 with more power, thanks to a compression bump from 11.0:1 to 12.0:1. The four-barrel version, designed more or less for stock car racing, was rated at 390 horsepower, while a drag-oriented dual-quad version was underrated at 405 horsepower. Another version was offered with 13.0:1 compression and was also underrated, this time at only 410 horses.

Perhaps the ultimate expression of Pontiac’s Super Duty program was the brief, 12-car run of 1963 Tempests equipped with the dual-quad, 405-horsepower 421 engine. Six coupes and six wagons were built and only a few are known to have survived the cutthroat ’60s drag wars. The best-known campaigner of them was Arnie “The Farmer” Beswick, who raced the famed “Grocery Getter” wagon.

 

CHRYSLER 426 STREET HEMI

Hey, we couldn’t do a story on milestone muscle car engines and not include the legendary 426 Street Hemi. It is not just an engine. It’s an icon of Detroit’s better days.

The Street Hemi got its start when Mopar launched its new racing engine for the NASCAR circuit in the early ’60s, where 426 Hemi-powered race cars finished first, second and third at the 1964 Daytona 500. Richard Petty won the race, after leading 184 of the 200 laps in his Plymouth.

Not surprisingly, the immediate and obliterating success of the new Hemi caused a stir, particularly among those racers who didn’t have one under the hood. After a few more races with similar results, NASCAR moved to restrict Chrysler’s not-so-secret weapon by imposing a “production model” rule. 

Chrysler was unprepared to offer the racing-only 426 Hemi in street cars. The company sat out the ’65 season while it prepared to retaliate. They returned in 1966 with the all-new, 426 Street Hemi and Chrysler quickly went racing again. There was little that was significantly different between the racing engine and the street version. The Street Hemi received two four-barrel carbs (the racing version had a single carburetor), lower compression, different valve timing and iron cylinder heads.

In 1966, the 426 Street Hemi was rated at 425 horsepower (gross) and 490 lb.-ft. of torque. It would remain in production through the 1971 model year, with its horsepower rating unchanged. Street Hemi-powered cars quickly became the stuff of legend and myth at small-town burger stands and urban street-racing venues. They developed a reputation for being unbeatable – when they were properly tuned. The Hemi required constant attention and tuning, particularly the carburetors, but when all was properly dialed in, the only thing that could catch a Street Hemi was another Hemi.

 

 

BUICK 455 STAGE 1

Although Buick was never a mainstream muscle car manufacturer, it produced perhaps the era’s biggest torque monster in the 455 Stage 1. Rated at 510 lb.-ft. at only 2,800 rpm, in its 1970, high-compression edition (with 360 horsepower), the Stage 1 helped launch the A-body-based Gran Sport and GSX models with tremendous grunt. In fact, its tremendous low end fueled debates about whether a Stage 1-equipped Buick was quicker than a Street Hemi car.

The 455 was a new, larger-displacement version of the Buick V-8 for 1970 and in its “normal” guise, it was still a torque monster. The Stage 1 package added a “bigger” cam and higher-flowing cylinder heads. The cam specs included a whopping 0.490-inch lift, with 316 degrees duration on the intake side and a long, long 340 degree duration on the exhaust side. As for the unique heads, they featured reworked ports and large 2.120-inch intake and 1.755-inch exhaust valves.

Even after the muscle car era started to wane with the lower compression ratios of 1971, the 455 Stage 1 retained its torque-heavy characteristics. It lasted for several more years, but even with lower peak horsepower and torque ratings, it still had more pull going for it than just about any other V-8 available.

 

CHEVROLET L-88 427

Sure, there are plenty of Chevy big-block engines we could cite for our list – and we’re bound to catch flak for not including the LS6 454 – but when it comes landmark power plants, the L-88 427 stands apart from the rest. It also laid the foundation for the COPO 427 engines and the 454 engines that would follow it.

The L-88 wasn’t a production-line item. Each was built at the Tonawanda, New York plant, but off the line. Its specs included an iron block and aluminum cylinder heads (with 2.19/1.88-inch valves), a high-lift, solid-lifter camshaft, a 12.5:1 compression ratio (through mid-1969) and a huge, dual-feed Holley four-barrel carburetor mounted atop an aluminum, high-rise intake manifold. That tall intake required greater hood clearance, prompting the design of the iconic L-88 hood scoop on the Corvette.

The L-88 engines built from 1967 through early 1969 had closed-chamber cylinder heads, while engines built in roughly the last half of 1969 were quipped with open-chamber heads. The change lowered the compression ratio from 12.5:1 to 12.0:1, but the open-chamber heads breathed better, so it was essentially a wash when it came to horsepower. To be honest, accurate horsepower ratings for the L-88 were difficult to come by in the early years. To keep the collective forehead vein of the insurance industry from throbbing, Chevrolet rated the engine at 430 horsepower, but the true output was more like 530-560. Extracting 600 horses from the L-88 was almost as easy as getting a speeding ticket with it, too.

 

FORD BOSS 302

As the Sixties drew to a close, SCCA’s Trans-Am racing series gained greater attention and prominence when it became a third venue for factory-backed performance competition, behind stock car racing and drag racing. Rather than big-displacement power, Trans-Am race cars needed high-revving small-displacement V-8s and Ford’s purposeful Boss 302 help racers like Parnelli Jones win plenty of races.

The clackety, solid-lifter “G”-code Boss 302 featured unique, large-port Cleveland-style cylinder heads, with poly-style staggered valves, needed the airflow velocity at the upper rpm range for optimal performance, so the engine didn’t really come alive until the tach needle swept past the 4,000-rpm mark. Its 290-horsepower (gross) peak was achieved at a then-stratospheric 5,900 rpm, with 290 lb.-ft. of torque registering at 4,300 rpm.

To ensure the Boss 302 stayed alive during its high-rpm runs, the bottom end featured a forged, cross-drilled crankshaft and heavy-duty forged-steel connecting rods. Even the block was cast with an extra dose of nickel for added strength, along with a thicker deck and four-bolt main caps. At a glance, Boss 302 engines are identifiable by their unique valve covers and extra-wide intake manifold. That manifold, a dual-plane, high-rise type, propped up a 780-cfm Holley four-barrel – more than the street car needed for everyday driving, but required for Trans Am homologation.

Despite its brief, two-year production run (1969-70), the Boss 302’s influence lasted long after.

 

 

Above Photo Courtesy of General Motors.

CHEVROLET LT-1 350

With nearly 60 years of history, the Chevy small-block deserves a place on just about every engine list you can dream up, but in the muscle car era its best iteration came in the 1970 LT-1 350.

The LT-1 was the engine in the all-new, second-generation Camaro Z28. It used solid lifters, 11.0:1 compression, a high-performance camshaft to maximize airflow, and a large, 780-cfm Holley four-barrel carburetor mounted on a special aluminum intake. The design of the LT-1 intake proved so efficient that many aftermarket performance intakes were simple copies. Blowing through rams horn-type exhaust manifolds and a low-restriction exhaust, the ’70 LT-1 was rated at 370 horsepower and 380 lb.-ft. of torque.  More than its dyno numbers, however, the LT-1 was renowned for its high-revving capability and broad, flat power curves. It was arguably the best production small-block ever.

As with all the other muscle car engines, the LT-1’s power declined in 1971. Thanks to lower compression, it was rated at 330 horses and 360 lb.-ft., but at its core was the great-revving character of the original.

PONTIAC 455 SUPER DUTY

The muscle car era was definitely on the decline by 1973, with compression ratios continuing to fall, insurance costs continuing to rise and a national fuel crisis making the term “V-8” almost a swear word. Still, there were some diehard performance fans who didn’t want to let go of the good-old days. Their choices were slim, but many found refuge in the little-known 455 Super Duty engine option offered in the Firebird line.

The 455 Super Duty all the trappings of a true muscle car engine, with a special, stronger cylinder block (including four-bolt mains), a high-lift camshaft, high-performance oiling system and a variation of the Ram Air IV cylinder head. It was rated at 290 horsepower and offered for two model years. Compared to 425-horsepower Street Hemis offered only a few years earlier, the Super Duty’s 290 horses doesn’t sound like much, but keep in mind that by the time it hit the street, factory supercars were basically tape-stripe specials. There was also that satisfying torque that simply can’t be masked by 455 cubic inches.

Not surprisingly, original Super Duty Firebird Formulas and Trans Ams are among the most collectable vintage Pontiacs. They represent the last bastions of the muscle car era.

 

FORD 5.0-LITER

No, the Ford 5.0-liter V-8 wasn’t part of the original muscle car era, but it is definitely a remnant of it and a bridge to the current golden age of factory high-performance. The Windsor small-block-based engine technically got its start with the launch of the Mustang’s Fox-body generation in 1979. That was only a few years removed from the muscle car era and its high-output version debuted in the Mustang GT in 1982. That car is credited with reviving performance in Detroit, as tens of thousands of customers affirmed the pent-up demand for a new muscle car.

In the following years, the 5.0-liter gained traditional performance items, including a Holley four-barrel, high-lift cam and exhaust headers, but it came into its own in 1987, when new, high-flow “E7” cylinder heads expanded its performance range and took horsepower to 225. Again, that wasn’t a lot when compared to the classic muscle cars or even the lowliest passenger cars today, but in 1987, there weren’t many cars with more power.

Like all the engines on our list, there was more to the 5.0-liter than just its horsepower numbers. It became a cultural force that drove both the auto industry and the aftermarket performance industry. For the Generation Xers who were too young for the original muscle car years, a Mustang 5.0-liter is their Chevelle SS-396.

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