This might be far fetched, but I wonder if there is anything at all different about the new shortblock that I got--something that would affect cooling or anything for that matter? I have to assume the SVHO shortblock has been exaclty the same for a couple of years. But I don't know that for sure. I bought the engine through Jerry, so I have to assume everything is the same. My builder didn't comment on any differences whatsoever.