Le Temps des Series'

I would like to fit a 2.5 tdi disco engine in the old 1967 series. (I will keep the old petrol engine to be able to restore it one day)
The question is

What legal requirements do I need to fullfill to stay within the french law.
The 88 has it's carte gris and control technique.

First lesson : 'Impossible n'est pas français' is false
It's almost impossible to fit such an engine in a Serie while keeping you vehicle street legal ...

True .
It wont match the "MINES" break requirement and wont be LAND ROVER FRANCE approved so
the case is closed ...

One exception, to find an old CARTE GRISE with the "MOD" written on it , the one of a guy who has modified something years ago and succeed to pass it when the rules were poorer . They dont keep paper memories of theses cases so....

Second exception, a modification accepted in GB and a "Carte grise de collection " obtained
by the FFVE in FRANCE;