Renntech’s latest restomod project resurrects one of Mercedes‑Benz’s most celebrated engines—the M120 V12—and pushes it into territory few expected. The result is the Renntech SEC V12 Sledgehammer, a handbuilt widebody homage to the C126 SEC that pairs old‑school mechanical drama with modern engineering precision. The project centers on a bored‑and‑stroked M120 that displaces 7.5 liters and produces 660 hp and 650 lb‑ft of torque, a configuration Renntech says will be limited to 12 examples and delivered beginning in 2027.
The M120 Legacy and Why It Matters
The M120 V12 is legendary: introduced in the 1990s, it powered flagship Mercedes models and later found a second life in hypercars such as the Pagani Zonda and the CLK GTR. Its naturally aspirated character—high revs, linear power delivery, and a distinctive V12 note—made it a favorite among tuners and collectors. Renntech’s decision to reengineer this engine taps into that heritage while demonstrating how classic architectures can be reimagined for modern performance.
What Renntech Has Done to the Engine
Renntech’s engineers have increased displacement to 7.5 liters through careful boring and stroking, upgraded internals, and bespoke intake and exhaust systems. The build includes hand‑built equal‑length headers to shape the exhaust tone and optimize flow, and a bespoke manual transaxle to preserve a pure, driver‑focused experience. The package is designed to extract maximum naturally aspirated power while maintaining reliability through modern materials and engineering practices. The claimed output—660 hp and 650 lb‑ft—places the Sledgehammer among the most potent naturally aspirated Mercedes builds ever created.
Chassis, Brakes, and Widebody Craftsmanship
Renntech pairs the reworked V12 with a handcrafted widebody shell that modernizes the C126’s proportions while honoring its classic silhouette. The widebody is complemented by forged two‑piece wheels, carbon‑ceramic brakes, and a bespoke suspension setup tuned to handle the engine’s torque and the car’s increased performance envelope. The result is a car that looks like a classic SEC from a distance but reveals contemporary performance engineering up close.
Driving Character and Experience
The Renntech SEC V12 Sledgehammer is engineered for visceral engagement rather than lap‑time perfection. The manual transaxle and naturally aspirated V12 emphasize throttle response, mechanical feedback, and an emotional exhaust note—qualities that modern turbocharged engines often struggle to replicate. Renntech’s approach is deliberately analog: the car is meant to be felt as much as it is measured, delivering a driving experience that prioritizes connection and drama.
Exclusivity and Market Position
With only 12 units planned, Renntech positions the Sledgehammer as a collector’s restomod that blends rarity with bespoke engineering. Buyers are paying for craftsmanship, historical resonance, and a unique driving proposition: a modernized classic that retains the soul of the original V12 era. The limited run and handbuilt nature place the car in a niche market alongside high‑end coachbuilt and restomod projects, appealing to collectors who value authenticity and mechanical artistry.
Why This Project Resonates
The Renntech M120 revival matters for several reasons: it demonstrates how legacy engines can be upgraded without losing their character; it shows that there remains a market for analog, driver‑centric machines in an era dominated by electrification and forced induction; and it highlights the craft of restomodding—where design, engineering, and storytelling converge. For enthusiasts, the Sledgehammer is both a technical achievement and a cultural statement: performance can be modernized without erasing the past.
Conclusion
Renntech’s SEC V12 Sledgehammer is a bold reinterpretation of Mercedes‑Benz heritage: a 7.5‑liter M120 that channels the drama of classic V12s through modern engineering and artisanal build quality. Limited to a dozen examples and tuned for emotional engagement rather than headline lap times, it’s a reminder that automotive passion still thrives in bespoke projects that honor the past while pushing technical boundaries.
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