440_magnum, I share your "opinion" about fact and fiction. Some things just don't hold water. I was not ignoring what you said earlier about strange flow patterns at high rates, in fact I believe a fast flow, within reason, works best and helps strip off the layer of tiny bubbles that form on the insides of the water jackets. If you put water in a pan and heat it you can see the bubbles form long before the water gets to the boiling point. About cavitation, I have seen damage in pumps that looks like corrosion pitting, but no corrosion. It is caused by the vacuum bubble collapsing and the water hitting the metal so hard it strips away some of it. I think the problem with most water pumps is that they were made to be simple, cheap and good enough to work most of the time at low rpm. A nice impeller would be great. I have used flow cooler disks on other engines but am not sure if they would fit on the back of a slant impeller. Well, it would fit on the impeller but might hit the block. I'll check this out in a few weeks. It's not as nice as a high tech impeller but helps allot and is cheap and easy.