Who manufactured the international harvester I4 196 engine?

International made their own gas engines: 152, 196, 266, 304, 345, and the 392. They're all high torque, tug-boat type engines. There massive, sturdy, and will easily run for 300,000 with regular oil changes and maintenance. Some modern engines might can boast equivalent life expectancies, but through the 60s, 70s, and 80s this was unheard of.