history of the international C60 engine

[danmcdonald]

Would the 154 crank have a pilot bushing hole?

[Boss Hog]

some do early ones I am guessing

[Bus Driver]

In 1953, the main bearing mounts in the block and the caps for the mains were changed. Very different configurations, with the change being-- in my opinion-- a big improvement. Nothing visible from the outside and not affecting the ability to install in one tractor or another. The change was a "running change" - during the model year and not at the beginning or end. First engine serial is in my files somewhere and probably in a prior post on this or another forum-- but the files are not easily accessible today.
Numerous changes in internal parts as the years went by-- but the main bearing is the major change to the engine block.