b29, like in Chevron B29 I guess.
It is said that the ROC F2 engine was designed by Mario Illien and developed by Hans Funda.
The N9T bottom end is the last and best iteration of the Simca-Chrysler engine but not so special, you can find some N/A Tagora and Matra Murena with the "N9T" cast on the cylinder block.
Try the French Autodiva forum for more info about your car:
http://www.autodiva.fr/forum/viewforum.php?f=2