This Old-School Engine Is Still Beating Modern Motors

Most of the major automakers around the globe moved on to the likes of dual overhead cams, variable valve timing, and multi-cylinder complexity decades ago. There is a brand which refused to let go of the old tech and still uses it to keep pace with modern engine units that rely on advanced technology to squeeze out more power and more speed. This is the story behind that engine, an architecture that is still winning, even after most of the industry abandoned it.

The Entire Industry Moved On From Pushrods, For Good Reason

A quick engineering crash course before we move further. During the early days, most engines followed the pushrod format, a layout which used metal push rods to transfer motion. The invention of dual overhead cams, better known as DOHC, changed the game. The DOHC layout, with four valves per cylinder, has the clear advantage in performance. These power units breathe better at higher rpms, which means more peak horsepower and more speed. The earliest example of the new tech winning was Peugeot at the 1912 French GP.

How DOHC Suddenly Emerged As The New Way

The "pushrods are dead" narrative has been in the headlines since the 1970s. Magazines, engineering textbooks, and marketing departments have all gone behind the same thing. The joke writes itself: every time the pushrod is buried, someone forgets to tell the dirt. Every whiteboard in Stuttgart said pushrods were obsolete, and the industry was running behind the DOHC as if it was a religion. NASCAR is one of the few professional venues where pushrods survive, and critics say that is because of a rule loophole.

Pressure Of Emission Control And Efficiency Targets

Another reason that took the pushrods out of the boardroom is the pressure for emission control and efficiency targets. With DOHC, it became easier for carmakers to implement variable valve timing, since the cams were already up top. During the early 2000s, horsepower per liter, also known as specific output, became a major marketing metric. A hypothetical 4.0-liter DOHC V8 making 450 horsepower has around 112 horsepower per liter, while an LS3 6.2-liter pushrod V8 makes 69. The pushrod looked primitive next to it.

One Company Refused To Follow, And Bet Everything On A 70-Year-Old Design

Engineers ofGeneral Motorswent back and forth on their internal testing grounds around 1992. One had a pushrod V8 and the other had a DOHC engine. When the drive was done, the officials unanimously went for the pushrod. The outdated engine outperformed the big new kid on the block in the blind test, and the snappy throttle response and the power delivery low in the rev range did the talking.

Practical Evidence Mattered More Than Everything

That was the life-changing moment for pushrod engines, and the test kept the architecture alive for a longer period. Remember, every other manufacturer went the opposite way. Mercedes was going DOHC across the board. Toyota was running DOHC on everything. GM was alone going pushrod, but they ran a test and chose what proved worthy. It was the pushrod, fair and square.

Efficiency And Cleverness Combined

Another reason the pushrod V8 is still one of the best old-school engine layouts is that it is so compact. A pushrod V8 is smaller than a DOHC V8 of the same displacement, because the cam sits in the block valley rather than on top of the heads. The engine gets shorter and narrower, and can be placed lower in the chassis, which means a lower center of gravity and a flatter hood line.

The Chevy Small Block Is The Most Successful Engine Architecture In American History, And It's Still Going Strong

Now, enough of the engineering crash course. Let's talk about the power unit. The engine that went over five generations and seven decades has produced more than a hundred million units. It is staggering for one engine architecture to have given life to so many cars. It is the 376 cubic-inch direct injection unit inside the Cadillac CT5-V Blackwing, making 668 hp and 659 lb-ft, and you'll get it when I put the other name to it: the LT4. It is hand-built by a single technician from start to finish, and once it is done, the engine is signed by the man who built it. The customer can see the name of the man who put it together from the ground up.

The Birth of America's Greatest Engine

The very first pushrod small-block was born back in 1955 when Ed Cole and his team introduced the 265 cubic-inch Turbo-Fire V8 in the Corvette and Bel Air. The first generation ran from the 265 cubic-inch base up to the 400 cubic-inch variant, and it became the blood and spine of American motoring history. The second generation came in 1992 with reverse cooling flow. The third generation, five years later, brought cast-aluminum blocks and took the game international. Gen three and gen four collectively became the LS family, with the fourth generation arriving in 2005 with the LS2, LS3, LS7, and LS9. The fifth generation, introduced in 2014, brought back the old-school names with the LT1, LT4, and LT5, plus direct injection.

The LT4 Small Block, The Evergreen Engine

The chief engineer of the Blackwing, Mirza Grebovic, described it to GM Authority as an engine that used to be a high-volume one but is now exclusive enough to have one engineer build it from start to finish, with a plaque carrying their name. Sounds familiar, right? It is the same "one man, one engine" philosophy AMG has built its reputation on for decades. The Blackwing is one of the most prominent sport sedans in America, and it carries the LT4 that iscapable of embarrassing rivals.

The Blackwing does the 0 to 60 mph sprint in 3.4 seconds with the 10-speed automatic, and 3.6 seconds with the six-speed manual. The top speed is claimed to be over 200 mph, and the weight is around 4,140 lbs. Cadillac has been slowly pricing it higher throughout the years, and the Blackwing now asks around $96,000 for the current model year. The biggest point is what we mentioned earlier: 108 million small-blocks built across seven decades, more engines than the lifetime output of every Mercedes, BMW, and Audi V8 combined, by a country mile.

Why A "Primitive" Pushrod V8 Keeps Challenging Engines With Twice The Technology

The primitive pushrod, as many call it, is still one of the biggest challengers for DOHC cars with more tech. Let's compare the Cadillac CT5-V Blackwing alongside its German competitors: the BMW M5 G90, the Audi RS7 Performance, and the Porsche Panamera GTS. That is a three-versus-one right there.

Three German Rivals, One American Answer

The G90 M5 is the heaviest M5 built yet, weighing around 1,250 pounds more than the Blackwing, and BMW snuck in a hybrid system that obviously did not help with the weight. The Blackwing is still around $26,000 cheaper than the BMW, the cheapest of the German trio. The most expensive of all is the Porsche, and the Audi takes the middle ground.

The 6.2-liter supercharged OHV pushrod V8 is the biggest of the lot by capacity, yet the Blackwing is the lightest car of the pack. The Audi has the fastest 0 to 60 sprint, but that is with the help of Quattro all-wheel drive launching off the line. Imagine having an engine as old as your grandmother and still being capable of beating the gen-Z kid with her walking stick. Remember, the Blackwing is being compared with the halo cars of Europe.

The Tuning Ceiling And The Monster From Hennessey

Hennessey went mad with the Blackwing and unleashed the beast. They named it the Hennessey H1000 CT5-V Blackwing. It makes 1,000 horsepower and 966 lb-ft of torque, with a Hennessey-claimed 0 to 60 mph in 2.5 seconds. The upgrade package costs about $55,000 and the car comes close to a $200,000 price tag. It was limited to 100 examples, with only 40 built. They put it up against a stock C8 Corvette Z06, the mid-engined American supercar. The Corvette had to eat dust, because the Blackwing, a four-door family car, was too fast. It was the pushrod that powered it to victory.

The H1000 sits at the top of the LS swap pyramid. At the bottom is the fact that you can grab a running 5.3-liter truck LS out of a scrap yard, shove it under the hood of almost anything, and make more than 400 horsepower for less than $500. This is something the German rivals cannot even think of doing.

The Engine That Refuses To Die, And Why It Never Will

The LT4 is the kind of engine that refuses to die. The cam-in-block layout produces a physically smaller engine for a given displacement, which lowers the hood line, drops the center of gravity, and spreads the weight evenly across the car. The pushrod setup needs fewer parts, which means less weight overall, and that gives the Blackwing a weight advantage over a DOHC rival with the same power output. In a car where even the slightest addition of weight affects the handling, that matters. The 4,140 lbs weight was not accidental. It was a direct byproduct of sticking with the pushrods.

The GM EV Reversal

In May 2024, Cadillac officially revised its plan of going all in on electrification. The brand now says internal combustion will coexist with the electric variants, which is more good news for the pushrod. The small block that everyone dismissed as primitive more than three decades ago has fuel left for the next century. The pushrod V8 survived because it was never outdated. The industry thought that just because it is simple, it is inferior. The engine that emerged in the 1950s still has fuel left for a long fight, and that is the story of one of the most underestimated engine units in American motoring history.

Sources: Hennessey, GM Authority, GM Media, Cadillac Society