The Matra looks good I have never seen one and wouldn't have known it has a V4! The later 96's had 1700cc engines and the Sonnet IIIs. But you are right the camshaft etc you have mentioned will suit both. If you are going to the trouble of higher lift cams and up rated valve gear then to get most benefit you certainly need to open out the inlet and exhaust tracts on the heads and consider the bigger valves. I don't know what carb you are running but again a twin choke weber makes a tremendous difference even without any other mods.