I ran across this and found it fascinating. It is all in Japanese (so I used google translate) - the premise seems to be that the M119 block has its origins in the old M116 3.5L block, and therefore the 5.0L and 6.0L M119s dont have optimized coolant flow through the block. The author seems to be trying to address it by ... well ... all this is way above my head, but it is fascinating to read.
https://translate.google.com/transl...benznetcom.blog81.fc2.com/blog-entry-859.html
https://translate.google.com/transl...benznetcom.blog81.fc2.com/blog-entry-859.html