I have looked into the SCCA rulebook which has been very helpful. But for the FIA rules are not enough, you have to provide evidence that a given system was used in period on the same car in International racing. Not easy.
My car has been raced in period by Earl Hurlbut (1971-77), Chip Boatright, Chris Peterson, Dan Vetrock , Dave Guertin.
The car is currently beeing refreshed and engine is out. I will post pictures once it is ready, hopefully within one month.