The I- monuts with bolts that go down the sides of the carbs rather than
the stud- flange mount on the regular sbn. The bolts should make them easier to get on/off in theory, except in practice they like to sieze. The bolt holes are at a different angle as well so i dont think they are interchangable.
(I am comparing 40i s to 38SBN .. in case there are other issues with size I dont know about)