I have a March 87T gearbox (not currently in a formula chassis). Per the notes I have, it can have "wide" or "narrow" gears. From what I am seeing in the box, this has narrow gears save for 5th which is wider. I have been told these share some internals with the Hewland DGB, but have not been able to confirm. Spare gearsets that were once with the car had disappeared before I acquired it. Can anyone confirm if the DGB gearsets are the same / interchangeable? If so, DGB gears would be considered "narrow"? Thank you!