You have asked a question which may well be unanswerable, absent an authentic build sheet for a particular car for a particular race.
Agree that the C7FE went over the counter w a 1967 part number, but Don Sullivan profiles, of which the C7FE is one at 107, were used with differing phasing in years prior.
These may give you some context:
http://www.shelbytransam.com/walt/ShelbyTA/images/road289gt40.pdf
https://historicdb.fia.com/sites/default/files/car_attachment/1601034601/homologation_form_number_191_group_gt.pdf
https://www.saacforum.com/index.php?topic=3222.msg28476#msg28476
https://www.goodreads.com/book/show/17239343-ford-small-block-v8-racing-engines-1962-to-1970