Fantastic sound. The smell of burnt rubber. Ridiculous power. Chrysler's HEMI V8 family had all of these traits since the first 331-cid (5.4-liter) FirePower unit entered production in 1951. The difference between them and other engines: a hemispherical (dome-shaped) combustion chamber. The advantages: Better airflow since larger valves can be fitted on the sides, more efficient combustion thanks to the centrally-positioned spark plug, and higher compression ratios. The end result: more power, baby!
Indeed, Chrysler's hemispherical chambers ruled the American automotive landscape for quite a while. Starting with the pioneering FirePower, the HEMI was soon able to be found everywhere, from streets to tracks and drag strips. Some even reached godlike status. Notably, the famous 426 7.0-liter Elephant HEMI V8 dominated the Daytona 1964 Daytona 500. We could go on forever, really, but the fact is that Chrysler didn't invent the hemispherical combustion chamber. Not even close. Its true origin likely lies in the Welch Model 4-L Touring, which had a two-cylinder water-cooled engine with 20 hp. In fact, many other automakers used the concept — and not just in V8 engines.
But of course, in this piece, we'll keep things simple and refuse those inferior motors from appearing in the same breath as Chrysler's omnipotent engines. Below, you'll only be greeted with V8 HEMI engines not built by Chrysler. Just don't call all of them HEMI, because it's a registered trademark of the Chrysler Corporation (Stellantis). Only one company had them made under license, which allowed them to use the name. Got it? Let's dig in, then!
Toyota seems like an unstoppable force today. It's one of the biggest automakers worldwide, and its hybrid tech is killing it on the sales charts. Once, though, the Japanese giant was content with copying homework from others to make better cars. Six decades ago, Toyota even made a V8 HEMI engine, and its design clearly echoes Chrysler's 426-cid (7.0-liter) HEMI.
But how come so few people know about these engines? Well, they were specifically designed for Toyota's luxury vehicles sold in Japan. The first version, called the V, was a relatively small 2.6-liter V8 unit that was co-developed with Yamaha. It produced 113 hp and 145 pound-feet of torque, and it was implemented into the Crown 8 sedan. Yup, it was a far cry from Chrysler's HEMI V8, but it was still good enough for Japanese roads.
In 1967, Toyota introduced the improved 3V, which was now destined for the company's Century sedan. The larger 3.0-liter engine produced 143 hp and 178 lb-ft of torque. Six years later, it was later replaced by the 3.4-liter 4V, which had an output of 177 hp and 205 lb-ft of torque. This shows just how quickly Toyota moved to catch its rivals at that time.
Finally, in 1983, Toyota launched the 4.0-liter 5V, which produced 188 hp and 239 lb-ft of torque. This was the last engine of Toyota's HEMI lineup; the company then went global with the Lexus LS400's 4.0-liter 1UZ-FE V8 in 1989, while the Century received the brand-new 5.0-liter V12 1GZ-FE engine in 1997.
Picture it: the 1964 Daytona 500. The starting grid: a nice mix of Plymouth, Ford, Dodge, Mercury and Chevrolet cars. At the finish: three Plymouths powered by Chrysler's legendary 426 HEMI V8. This might've been the engine that brought the HEMI brand to the forefront, but it also forced Ford to react with its own take in the form of the 427 SOHC 7.0-liter V8 Cammer.
Inspired by the success of its biggest rival, the Blue Oval went with hemispherical combustion chambers for its racing engine. Still, it had an overhead camshaft driven by a single chain rather than a set of gears. This had complicated things slightly; since the chain stretched under load, Ford implemented different valve timing on both sides of the engine. Moreover, the two camshafts were reverse copies of each other to ensure proper valve closing and opening.
It was far from the sophisticated solution you'd expect in a performance engine, but keep in mind that Ford developed the 427 Cammer in just 90 days. Besides, it was still enough for 616 hp at 7,000 rpm and 515 lb-ft of torque at 3,800 rpm with a single-barrel carburetor. A dual-barrel carburetor pushed those figures to 657 hp at 7,500 rpm and 575 lb-ft of torque at 4,200 rpm.
Unfortunately, NASCAR didn't allow the 427 Cammer to compete. The official statement was that this was a 'special racing engine.' Chrysler's 426 HEMI was banned for the same reason, but only after it obliterated the field. According to the Journal newspaper, though, NASCAR boss Bill France didn't like the idea of the exotic, 'European' SOHC configuration.
Yup, Chevy also built a V8 with hemispherical combustion chambers. Much like Ford's Hemi, the 302 Hemi-Crossram was an experimental engine developed to compete in the Trans Am racing series. There was no production car with this amazing engine — apart from one 1969 Camaro Z/28 with a 302 Hemi-Crossram built by the engine's designer, Smokey Yunick.
But what makes Chevy's Hemi such a legendary engine? To begin with, it produced 450 hp from just a 5.0-liter capacity. Moreover, it's a lightweight, all-aluminum unit with canted valves and Crossram intake. Of course, there's also the Hemi-head, which was developed specifically to tackle Ford's dominance in Trans Am with the Boss 302 engine. The head necessitated new camshafts similar to the ones found in Chevy's big-block V8s. The 302 Hemi-Crossram also had some exotic add-ons, like magnesium valve covers, stronger pistons, and two Holley 4295 carburetors.
So, how did the Chevrolet 302 Hemi-Crossram do against its competition? Unfortunately, it remained only a prototype. Chevy's 'regular' DZ 302 small block V8 was already dominant in Trans Am even without the Hemi heads, so there was no real need for an upgrade. The DZ 302 was already a legendary engine with an oversquare design (leading to a 7,000+ rpm redline), forged internals, and excellent reliability. Alas, it denied us the chance to see Chevy's only Hemi engine in action!
Before we delve into the Daimler SP250 engine, here's an important note: this is not the Daimler company associated with Mercedes-Benz, nor is it Daimler the truck company. It's the now-defunct British automaker that — back in 1896 — was named after Gottlieb Daimler's company, after founder Harry J. Lawson purchased the rights to the name.
Confusing? Absolutely. Regardless, Daimler has built some excellent luxury vehicles throughout its history, including attractive sports cars like the SP250. Small and lightweight, the SP250 epitomized what a British roadster is all about. Thanks to its fiberglass body, it weighed just 2,260 pounds, despite having a 2+2 seating configuration. And it had a ladder frame chassis. Yup, just like an SUV.
Still, the Daimler SP250 was advanced in other areas. It had hydraulic disc brakes on all four wheels and a fully synchronized four-speed manual transmission. But the main attraction was the 2.5-liter V8 designed by legendary motorcycle designer Edward Turner. The engine also had hemispherical combustion chambers, which Turner already used on Triumph's motorcycle engines. As a result, it produced 140 hp at 5,800 rpm and 155 lb-ft of torque at 3,600 rpm.
Thanks to the lightweight construction, the relatively small V8 propelled the SP250 to 60 mph in 8.9 seconds and gave it a top speed of 123 mph. Far from impressive, sure, but remember that the SP250 was launched in 1959. Still, it makes us wonder how good would the SP250 be with the closely related 4.5-liter V8 from the Daimler Majestic Major. The larger engine was also designed by Turner — Hemi-heads included — and produced 220 hp.
Aston Martin was already a force to be reckoned with in the 1950s and 1960s. It won the 1959 24 Hours of Le Mans with the DBR1 prototype. A year later, Sir Stirling Moss won the Goodwood on Easter Monday with the DB4 GT Lightweight. Then, in 1964, the DB5 starred in the James Bond movie, "Goldfinger." What each of those cars had in common was an inline-6 engine, which wouldn't cut the mustard anymore by the end of the '60s. Aston Martin needed a V8 to compete, and it finally arrived as the 1969 DBS 5.3-liter V8.
But this wasn't just any V8. It was designed by Tadek Marek, one of the greatest engine designers in automotive history. Tadek already designed the brand's inline-6 masterpieces, but this time, he also had more advanced technology – like Bosch's mechanical fuel injection system – at his disposal. The new engine was an all-aluminum design, but the block and crankcase were formed as a single sand-cast unit for increased rigidity. The crankshaft and connecting rods were forged for higher strength while the pistons were made from die-cast duralumin. For maximum performance, Aston Martin's V8 also had four camshafts and — of course — hemispherical combustion chambers.
The result? 375 hp and 398 lb-ft of torque in the 1972 DBS V8. It could do 0-60 in 5.1 seconds and reach a top speed of 158 mph. However, the last model with this engine — the 1999 Aston Martin Vantage Le Mans V600 — produced an astonishing 550 hp and 550 lb-ft of torque, courtesy of two Eaton superchargers.
The Tatra T77 looked like a spaceship when it first appeared in 1934. With its sleek and elegant design, the T77 took the 1930s streamlining craze to a whole new level. It was bold and cool at the same time; it even had a fin in the back! No rear window, either! Perhaps more remarkable still, the designer, Paul Jaray, worked on airship designs before. He even used wind tunnels to streamline the car's shape as much as possible. As a result, the T77 had an exceptionally low drag coefficient of 0.36. The T77's rivals at the time reached north of 0.5 Cd.
But its futuristic credentials weren't only skin-deep. The T77 also had independent four-wheel suspension. Meanwhile, magnesium alloys were used in the transmission, engine, suspension, and body to shed weight. But the star of the show was the 3.0-liter air-cooled V8 in the rear. It had hemispherical combustion chambers seventeen years before Chrysler launched the first HEMI V8! Of course, it wasn't a powerhouse. But even with 60 hp on tap, it propelled the slippery T77 to 87 mph.
Still, the T77A arrived just two years later with an upgraded 3.4-liter unit. The new engine produced 75 hp, enough for a top speed of 93 mph. Thanks to the longer wheelbase, the T77A could also accommodate six passengers in full comfort. However, by this time, the Tatra T77 earned its 'Secret Weapon' moniker. According to some reports, the car's tricky handling killed a few German officers, prompting the troops to stop driving in them.
Here it is — a HEMI-branded engine that's not made by Chrysler. Well, sort of. Energy Manufacturing only makes the forged-aluminum Mopar Gen III Hellephant and Drag Pak engine block; you still need to purchase other parts yourself. Still, you'll be getting higher-quality foundations for your tuned Gen III Hemi builds. These blocks are machined from a 490-pound block of high-grade forged 6061 aluminum, which gives them excellent strength and low weight.
Energy Manufacturing offers three different designs. The entry-level BBC billet block features 7/16" head stud provisions, 9/16" and 1/2" splayed main studs, and gives you the choice of 7075 aluminum or 4140 steel main caps. Meanwhile, the SBF brings high strength bearing bronze cam retention, 1/2" ARP main studs and 1/2" head stud provisions. Finally, the LS allows cross bolts on the main 1/2" ARP studs, making it the preferred option for high-horsepower builds. According to the company, its blocks are good for up to 2,000 hp in boosted builds. And it's not just the materials; Energy Manufacturing ensures each block is up to spec with a highly-elaborate 33-hour test.
Of course, the moving parts should also be strong enough to reach those power figures. Forged cranks, rods, and pistons are non-negotiable, but you'll also need new valve springs and a high-flow head to enhance airflow. Finally, upgrading the ECU will ensure everything gels together.