What a great race!
Merzario won that race and his co-driver was the greatest italian rallyman: Sandro Munari.
At the time Munari was one of the best drivers of the World Rally Championship, he had just won the Montecarlo (1972) in a Lancia Fulvia HF 1600. During his career he was also a good sportcars driver, but only in particular races, open roads like Mugello, Targa Florio or Nurburgring, and only at the wheel of "small" prototypes like Lancia F&M barchetta, Lancia Zagato, one or two races in a Fiat-Abarth 2000 Sport. Surely he didn't drive before a great 3 liters sportcar like a Ferrari 312P-B (the same engine of the 312B F. 1 ).
When he signed on Ferrari for the Targa (and then he ran also at the Zeltweg 1000 km), he wasn't afraid to drive a monster like the 312P-B, but tasted his ability in the race: he won the Targa (perhaps Merzario drove at his best, and Munari was conservative ;) ). The only thing he changed for the race was... the helmet: he drove with an anonymous white helmet (with only two little red and green rows) and not with his old famous helmet with a Drake hand-painted on top (his nickname at the time in the rallies was "Drago" = drake).
Do you think it's possible imagine something similar today? For example Sebastian Loeb winner of some race at the wheel of an Audi R8, or Petter Solberg in a Bentley?

Colin McRae drove this year at Le Mans 24 Hours a Ferrari 550 Maranello, and drove well.
But it's not the same thing, in my opinion...