Setup for the 617 in C111 body?

[dalek]

Does anyone know what Mercedes did when they ran a 617 turbocharged/intercooled engine delivering 230HP in a C111Mk3 body in Nardo in April 29/30 1978 for 12h, with top speed of almost 322Km/h? Did they change anything in the engine itself, whether cam or fuel pump? How about turbo choice?