I don't know, I've seen many many (over 50) fluidynes installed into FDs, never with a problem. I've been running mine without incident since 2000, my dad has been running his since 2003.

 

At some point, Fluidyne changed the upper radiator inlet tubing to make it longer. This was probably to let the fans mount more easily. I got one with the shorter filler neck, and had to cut my fan case to make it fit. My friend got a Fluidyne with the longer filler neck. His fans fit, but now his upper radiator hose is higher, and his stock airbox won't bolt down properly.

Check with Fluidyne to see if they will help you.