You are correct in saying there is two different pump arrangements for the 404.
The Turbo Built versions have the larger water pump. He did not specify that this is a turbo model, so while perhaps it was wrong of me to do so, I assumed he was referring to the non turbo model which is a different block entirely from the Turbo Built ones. The actual age of this engine can also determine compatibility as well. There were big changes made in 1969 that effected the tractor engines and more again later involving combine engines as well. There is much more information needed to say one way or the other.
I was 20 years late to the 404 update party I wonder what all is different on them? Physical castings different, that basically just share internals and have the same bell housing pattern? Or just more subtle but still significant changes?
And on the 8th day, God looked down on his planned paradise, and said "I need a caretaker." So God made a farmer.
i helped a fellow technician do this swap several years ago. I don't know the age of either machine, but it was pretty easy to do. Our biggest issues were we had to knotch the block for some linkages and had to modify the exhaust manifold to fit under the scv's.