I have my 91FZ mounted upright inside the cowling of a Balsa USA Nieuport 17. The large opening in the front of the radial cowling will allow plenty of air to enter all around the engine, however, the only exit area is at the bottom below the engine. I probably should have mounted the engine inverted so the air would flow in and out the cowling directly over the cooling fins but it will take a major operation to change it now. Do you think it will cool well enough like it is ?

I don't know, I can't see what you have.