Actually,
The International Truck and Bus Corporation is the only part of the original International Harvester (FARMALL) from the turn of the century. In 1985 when the IH Ag division was sold off to Tennaco (J.I Case) the International Harvester and IH "Man in the tractor" logo was sold to Tennaco. This is why the Engine, Truck and Bus company changed their name to Navistar, and then back to just International after they nearly went under with the name change. The last year I know I have seen the IH logo on and IDI was an 86 6.9, the 87 6.9 may have, but I have only seen Navistar on 7.3 IDI. The last IH/Navistar engine used in the Fords was the 6.4 through 2010. The new 6.7 engine is an in house Ford designed and built diesel. Also read an article that the 2016 medium duty F-Series (F-6,7,800) trucks are coming back in-house for Ford and will no longer be manufactured by Navistar as they are now.