Has anyone stuffed an 88" Twin Cam engine, gearbox, and primary into a late eighties FXR frame?  What will I run into?  Will I have to make any serious cuts on the frame? 

Was thinking of doing the same thing myself, and when I did some investigating, I was told by various people supposedly in the know that an engine/tranny setup from a twincam FLH(which has the shorter primary like the FXR)  will go in with only minimal modification required on the mounts. But as I said, I have only been told, and havent done the job myself. It can obviously be done , because I did see a guy on one who was riding on an MC poker run, but he left the run early, before I could  ask how much mods were needed to get it done.