Getting closer...:
http://webbase.transpro.com/catalog.php?partnum=398219
Fedco doesn't exist anymore; it was taken over by Ready-Aire. The only conversion link I have is:
http://www.autopart.com/radiatorinfo/heatercoretech.htm
but it doesn't work for some reason.
Your number 398219 is a GDI number. From the dimensions, I'm unable to find a Fedco number. Looks a lot like 2-199, but could be many others.