Not sure quite what that one in the 1st pic is, but it doesn't look much like my 406. The one marked as a 405 does. SR100 is correct, the v8's didn't get dropped in until the 407.
The 406 in the 1st pic is bodied by the Swiss coachmaker Carrosserie Beutler. Beutler had bodied handful of Bristols, as far as I know, the 406 was the last.