Finally dug out book, no scanner set up at the moment, so took a photo of the book.
at the left the original Hurricane intake can be seen, regarding this Massimo
I wonder if the width was as the usual air intake of Hurricanes, and if it had openings protected by mesh on the sides and lower part. Filters of Il-2s and Il-10 opened an hatch when the landing gear was retracted, but I don't think this is the case of these Hurricanes.
there are hinged parts on the sides of the front part, so perhaps this was a similar mechanism.
Hopefully some further information may come out when the planned Soviet Hurricane book by the authors of "Soviet Hurricane Aces" is published.
Wonder what colour the new parts were painted....
cheers
T