So, is it a 504, a 505, a 506, or "Project E27"?
Good point.
Projet E27 for a 504 Coupé seems to be correct, but the original title contained neither.
So ratapouet isn't strictly correct saying it's a 604.
But it's still a repost so maybe best to take his point away and just leave it merged?
Maybe change the title though to include a little more information?
Here are some more pictures, from which the E27 designation can be clearly seen; one German website declared it as by Pininfarina, which I haven't seen mentioned before either...