190 HP 617 engine ( by Mercedes )

Well,
anyone know how it was done, or how little of the 617 was left UNMODIFED
http://www.cartype.com/page.cfm?id=743&alph=ALL&dec=ALL
In 1976, Mercedes-Benz decided to disprove the old prejudice ? and what could have been better suited to providing counter-evidence than a C 111 with diesel engine? The engineers installed a three-liter naturally-aspirated compression-ignition engine with five cylinders in the C 111-II for the first tests. In the car, now called C 111-IID, the OM 617 LA engine developed as much as 190 hp, thanks to turbocharging and intercooling, as opposed to the 80 hp output of the production engine which powered the Mercedes-Benz 240 D 3.0 (W 115, Stroke Eight) and, at a later stage, other models. In June 1976, the C 111-IID reached spectacular speeds on the test track at Nardo near Lecce in Italy. In the course of 60 hours, four drivers established a total of 16 world records ? thirteen of these applying to diesel-engined cars and three to cars in general, irrespective of their type of engine. During the tests, an average speed of 252 km/h was recorded, and Mercedes-Benz proved impressively that diesels also have sprinter qualities.
Cheers,
Marcus