I met Robert on the National Aeronca Forum and told him that this was the place for him to come with his Seaplane questions. Someone must have researched the use if 1650s on a Champ.
I told Robert that I thought that regardless of them not being on the type certificate and not knowing of any STC for them, with a 100 HP C-85 I thought they would add too much weight.
Since he is in Canada, that makes this more confusing based on the different rules and regulations in Canada compared to the U.S.
Robert, Try Ed Peck. He makes EDO parts up there North of the Border. He may have an answer. And, if you need the contact information for J.J. Frey, let me know.