F40 question

at what point in the production in 1990 did the factory start putting that tube on the left side of the engine to redirect airflow at the waste gate?

my car was finished in september of 1990, and has it, but all other 1990 cars i have seen do not, whereas all the 1991's do have it.
since it took about 3 months to build one, the change must have occurred in June of 1990.

anybody know more?

 

i think i found the answer myself. the car was finished in september, but the factory was shut in august - when the car was only partially built.
given that august is the time all of italy, including modena, shuts down, its like a new year in september.
thus the new elements going onto the 91's were already added as of september when the factory restarted.
so altho mine is a 1990, the engine bay layout and equipment is to 1991 spec.
which is guess is kind of lucky since the heat reduction is slightly better.