I would have never thought that a fender from an FL softail would have fit an FX fork. I just happen to have both a Fatboy and a Heritage front fender in my shop. Thanks for the info.

 

Attached are Mock-Up photos of an experiment I performed on my 03 Train. The rim is stock, off an 02 Heritage with a 16 x 140 series tire mounted on it. The fender is from a like-era Fatboy. Everything lined up and bolted on nicely without the need for fabrication work.

My plan was to trim the fender down however I didn't follow through with the modification due to erratic handling characteristics of the 140 series tire.

 

Since you mentioned the change in handling, I will chime in on that as well. When I initially did the swap, the front end became heavy, with noticeably more wheel flop during slow speed cornering. This is because of the difference in wheel diameter. The 16" with a 150 tire drops the front end about 3/4". Doesn't sound like much, but it's enough to change the trail and affect handling. I just installed bolts and dropped the rear 3/4" to compensate. Handled just like stock after that.