The Motorcraft catalog lists part# FD 4604 fuel filter. Most parts stores, including the local Motorcraft distributor are trying to sell me a FD 4616.

whats the deal? has FD 4616 been updated/replaced with FD 4604? do they interchange?

 

FD4616 is the right one. Look here.
Ford 6.0 Liter Turbo Diesel Truck Filters, Air Filters, Oil Filters, Transmission Filters And Glow Plugs - Diesel Filters,Additives,brake rotors, and brake pads for Chevy, Dodge and Ford Diesel Trucks

 

FD 4604 has been replaced with FD 4616.

 

Installed the FD 4616 last weekend. Filter appears to be same. only difference I saw was the O-ring they supplied for the large Cap is now Green.