RENNtech has announced the SEC V12 Widebody Sledgehammer, a limited-production restomod that addresses one of the more interesting gaps in Mercedes-Benz history. The C126 SEC coupe—the two-door variant of the W126 S-Class that ran from 1981 to 1991—never received a V12 engine from the factory. Production ended just as Mercedes was finalizing its first V12 for the next generation. The Florida-based tuner, founded by former AMG engineer Hartmut Feyhl in 1989, is building the V12-powered C126 that Mercedes never made, and they’re doing it with the largest displacement variant of the M120 engine ever assembled, and only 12 examples will be built.
Engineering The M120 To 7.5 Liters
The M120 V12 has serious pedigree — it powered the Le Mans-winning CLK GTR and became the foundation for Pagani’s entire early supercar lineup. RENNtech’s version displaces 7.5L, which puts it beyond even the 7.3-liter AMG variant that Horacio Pagani used in the Zonda. Each engine gets hand-built in Florida with equal-length headers that deliver proper V12 acoustics. Output sits at 660hp and 650 lb-ft of torque, all naturally aspirated. That’s more than double what the top-spec 560SEC produced with its 5.6-liter V8, and it maintains the character of the original powerplant.
Full Coachbuilt Approach
Starting with a frame-up restoration, RENNtech widens the C126’s stance and integrates functional aerodynamic elements throughout the body. The flared arches are there to clear wider wheels and accommodate upgraded braking hardware. Ducting routes air for cooling and stability rather than aesthetics. The car also gets custom-forged wheels and a lowered ride height, but the proportions still read as C126 rather than some overwrought modern interpretation.
Each interior gets spec’d to the owner, which puts this build on the level of what Singer does with Porsche. Feyhl cut his teeth as the technical director behind the original W124 Hammer at AMG before establishing RENNtech, so the Sledgehammer name ties directly back to that widebody legacy.
Spec Sheet
Model: SEC V12 Widebody Sledgehammer
Platform: Mercedes-Benz C126
Engine: Hand-built M120 V12, 7.5L naturally aspirated
Power: 660 HP / 650 LB-FT torque
Limited Production: 12 units worldwide
Delivery: Starting 2027
Pricing & Availability
RENNtech hasn’t announced pricing yet for the Sledgehammer, but first customer deliveries are scheduled for 2027. Limited to just 12 custom examples, you can expect it to be in six-figure territory.
Recap
2026 RENNtech Mercedes V12 Widebody Sledgehammer
RENNtech just announced the Sledgehammer, a full coachbuilt restomod that puts a hand-built 7.5-liter V12 into the C126 SEC—the V12-powered coupe Mercedes never made from the factory. Only 12 will be built, with first deliveries starting in 2027.
