Here is what I found when I open up a 1984 flatreed engine(restricted install).
Look at the picture and you can see that the euro flatreed engine intake/reedcage area opening is unrestricted.
Thought I would share this since so many derbis are being found. I plan to open the 84 cases.
(anyone else tig welding the primary gear and output shaft and installing a soft plug into the disengagement hole.
I will show my broken parts a bit later)