I think there's a grain of truth in this story. This could have happened at recce of the '86 Portuguese rally, in which the Estoril track was the Rally HQQuote:
Originally Posted by 'Mirek Fric [Cze
that year (could be near the track too, I'm not sure). But indeed, it's still an unconfirmed story.
Though these words of Hannu Mikkola do make quite a clear comparison of Group B and F1 (at the opening scene of the video).
http://www.youtube.com/watch?v=nYhiJeRPgdw