Both the Mercedes Benz SL73 and some Pagani Zondas are powered by the 7.3-liter M120 engine
The Pagani Zondas are powered by three different displacement engines of the Mercedes-AMG M120 engine. The largest is a 7.3 –liter, normally aspirated V12 engine produced by Mercedes-AMG. Before providing these engines to Pagani to install in their Zonda, the exact same engines powered a select few, very special Mercedes Benz R129 SL sports cars called the SL73.
History of AMG and the M120
AMG, short for Messrs, Aufrecth and Melcher from GroBaspach started in 1967 as an independent engineering firm specializing in high performance Mercedes-Benz applications. The company first started building racing engines and cars for Mercedes-Benz, eventually branching out into modifying and tuning exclusive Mercedes-Benz road cars in much the same way as Alpina did with BMW and Ruf did with Porsches. Starting as an independent shop in 1967, Mercedes Benz became the sole owner of AMG in 2005.
By the time AMG started working their magic on the M120, it had already been in production for several years as a 6.0-liter engine. It powered all V12 Mercedes Benz vehicles produced in the 1990s.
The fourth generation Mercedes Benz SL Roadster, the R129 was produced between 1990 and 2002. The SL73 was the final version produced of the Mercedes Benz R129. It was followed by the Mercedes Benz R230.
To get an SL73, a person would have to buy an SL600 roadster and turn it over to AMG for a short period of time. For $50,000, the company would bore and stroke the engine and throw in an assortment of titanium parts. The finished product was a two-ton Mercedes Benz SL sports car that produced 518 horsepower and 553 pound feet of torque. This was good for a 0 to 60 time of 4.8 seconds, accelerating all the way to 186 miles per hour. While this is common in 2016, keep in mind that this was 1999, almost 20 years ago.
A big fan of the Mercedes Benz SL73
Needless to say, the Mercedes-Benz SL73 is a special car. With only 85 ever produced between 1999 and 2001, fifty of the SL73s were rumored to have been purchased by one man, the Sultan of Brunei.
The Sultan is the ruler of a small natural gas rich country on the Island of Borneo in Southeast Asia. He is worth an estimated $20 billion and really loves his cars. He is rumored to have an enviable collection of over 7,000 vehicles rumored to be worth in the billions.
The 7.3-liter M120 engine
Every Pagani built by from the beginning has been powered by Mercedes-Benz. Horation Pagani was very good friends with perhaps one of the best Formula drivers ever, fellow Argentinian Juan Manuel Fangio. Fangio gave Mercedes Benz two world championship titles in the 1950s.
To this day, Mercedes-AMG is the exclusive provider of bespoke engines to Pagani. While the M120 was used in several Zondas, bespoke versions of the M158 engine, producing over 700 horsepower have found their ways into several Huayras, including the latest Huayra BC. This special engine produces amazing performance in the Paganis because the vehicles weigh a bit over 3,000 pounds compared to over 2 tons for the SL73.
It is worthwhile to note that there are kits to make your M120 powered Mercedes-Benz sound like a Pagani. I am also aware of somebody creating a do-it-yourself kit.