As far as I know, the Mirages were an attempt by Ford Great Britain to develop the GT40 further.
The standard GT40 cockpit was considerably wider than the regulations allowed, causing excessive drag.
Len Bailey picked three tubs to modify. The most visible modification was the squaring off of the front of the monocoque, as distinct from the semi-circular cut out on the standard tub.
The front body panel was similar to the MkI GT40, although without the twin nostril radiator vent. Extra driving lights were fitted underneath the headlights, and small canard fins fitted just ahead of the front wheel arches.
The major difference in appearance was in the centre section and rear body cover, this being fitted with three NACA ducts.
The Cd was down to 0.33 from 0.35, and the weight reduced by 200lbs.
Regulations were changed for 1967 giving the Mirages only one season to prove their worth. Out of 14 race starts, they won 5 races! Pretty good with basically two chassis to work with.
At the end of the season, it was thought that chassis M1002 was converted to the great GT40/1075, and M1003 to GT40/1074.
A brief but very successful career.
Finally, may I wish all GT40 fans a Very Merry Christmas and a Happy New Year.
Long may the Forum flourish - It is a wonderful source of inspiration.