Sentiment is a powerful thing.
Like I said, pull it apart and check the crank journal diameter. If there is a difference, I'd say that is where it will be. It's likely that if the stroke is different, or the rod was a different length, then the piston would also have an IH part number, but it does not. Journal size is the only possible difference that makes sense. May also in fact be the same as a non IH motor, just uses that part number because of the tractor specific crank. With this older stuff, it's anyone's guess. But we can make some logical assumptions, and use calipers and mic's to learn a lot, lol.
