RENNtech Will Make A Modern Mercedes-AMG Hammer With A Hand-Made V12 Engine

Out of all of RENNtech's creations, few carried a more prominent name than the "Hammer," a concept that began with the iconic RENNtech W124 and the broader pre-merger heritage of AMG. Although it's been a long time since these cars were new, RENNtech is bringing back the Hammer name — and this time, it's a no expense spared, hand-built, restomod powered by a 7.5-liter V12 producing 660 horsepower. 

Called the Sledgehammer, the new creation will be limited to just 12 examples and is based on a fully restored Mercedes C126 SEC. Although it does resemble a well-known AMG-built 6.0-liter Coupe from the 80s, the Sledgehammer is a modern interpretation of what a top-spec SEC V12 should look like. The C126 never left the factory with a V12 under the hood, making this likely the final boss of all C126 Mercedes.

As the restomod market continues to grow thanks to modern reliability paired with old-school styling, big-dollar builds like this are becoming increasingly common. If you've never heard of RENNtech or you just appreciate the charm of vintage Mercedes big-engine coupes, here's why this car deserves your attention.

At the core of the Sledgehammer is the iconic M120 12-cylinder Mercedes engine — a powerplant that deserves a story of its own. While the M120 can sometimes be found in cheap used examples of older W140 S600s and R129 SL600s, it also appears in multi-million-dollar hypercars such as the $17.5 million Pagani Zonda HP Barchetta. For the RENNtech Sledgehammer, the M120 is rated at 660 horsepower and 650 lb-ft of torque. The hand-built, naturally-aspirated, race-inspired engine has gargantuan displacement — a combination that's hard to find in modern vehicles, even big luxury sport coupes. 

According to RENNtech, it's more than just an engine, though. The package includes: a widebody kit, a stainless steel exhaust with equal-length headers, performance cats, downpipes, and performance mufflers. RENNtech also aims to optimize the Sledgehammer's weight distribution and pair that with carbon ceramic brakes, custom 19-inch wheels, and a manual transaxle. RENNtech claims that the widebody kit improves aero, cooling, and stability, and we'd love to see this thing in a wind tunnel to see proof of those claims.

Although 660 horsepower is certainly a lot, it's not a staggering ratio when you consider the displacement. With 7.5 liters, the Sledgehammer delivers about 88 horsepower per liter. By comparison, a modern high-performance turbocharged 2.0-liter engine like the one that powers the Civic Type R produces 315 horsepower, or roughly 158 horsepower per liter. The M120 is also incredibly heavy (approximately 661 lbs without fluids), and it drinks fuel with two straws. So it's not all about the raw power.

It doesn't have a lot of horsepower per liter, but cars like the Sledgehammer tell a more profound story than just numbers. The M120 is a symbol of an era when luxury performance meant mechanical harmony. The feeling that the engine was operating far below its limits was part of the character that many enthusiasts miss today. Combined with minimal electronics, the Sledgehammer and its M120 evoke the feeling of a time machine, one that transports the driver back to a time where cars were simpler (well before the complicated turbocharged, supercharged, mild-hybrid engines made their way into luxury flagships). 

Back in 2023, we said that some of the then-current V12 cars might be the last V12 cars ever made. Fast forward a bit, and things are not looking much better. As of last year, only 11 cars with V12 engines were available from major manufacturers. Out of the 11, only three were naturally aspirated. The worst part is that V12 numbers are likely to continue dwindling going forward. So an engine like the naturally-aspirated old M120 is extremely compelling for its character and its increasingly-rare cylinder count, on top of the extra performance and provenance provided by Renntech.

The appeal of such a vehicle in 2027 is easily understandable. Last year, we asked you what the worst things are about modern cars, and many of you noted the lack of tactility and annoying advanced driver assist systems. However, probably the most palpable criticisms were that some modern cars can feel a bit soulless and lacking sensory details, and that is exactly where the Sledgehammer speaks the loudest.