hey dave!
several years ago bruce kown was working on an f-220 conversion for the 14-13. don't know how far he got, but it might be instructive to talk to him. try him at:
Bruce Kown
Classic Aire, Inc
Cartersville , Georgia
770-386-7435
c.aire@mindspring.com
hope this helps!
blue skies,
vic & N522A