[Brian]

I have come across two of those blocks with the 'super clean' water jackets. One other feature they have is the third hole drilled and tapped at rear of block for oil cooler. They seem to be a very high nickel casting. One of those blocks came out of a bren gun carrier; very low mileage, it still had V8 branded sparkplugs, never seen those before either....anyway, my experience with these blocks is that they crack big time!! In both instances, these blocks have cracked in numerous weird places, neither block was abused. I now avoid them. You think when you find one, 'wow! what a great block; no corrosion, you spend lots of money machining them up, then, down the track you start getting water into cylinders etc. Gets somewhat demoralising...your experience may differ, for your sake I hope so, good luck