On the YB in my Cat, I have removed the stat,pulley, and have removed all bearings,shaft,impellor from the waterpump assembly, and am having the holes welded.I maybe pedantic, but didn't like the thought of the old waterpump assembly sat there as a potential leak point.
I will try the pump this summer, and if it proves unsuccessful it will be relatively straighforward to fit a conventional pump and stat back into it.
Bob, once again, many thanks for your input on this, it has been extremely eye opening.
p.s, know anyone with a decent YB 4x4 bare head for sale?