Got my hands on a E8400 yesterday and will set it up for some testing with that chip. If the board can handle it (ASRock P43DE3), I'll see how high it can go with some testing done with it as well.

Set it up and did a run like the others with it.
Just as easy to setup with the 775 as it was with the AM3+ and the installation was a snap.

With the 775's equal spacing of the cooler mounting holes, I was able to turn it any way I wanted to but did it so that I could use all four RAM slots with any RAM sticks I wanted to use, plus with the cooler being as close to the sticks as it was, it actually gave a cooling effect to the sticks.
One thing I did note is again with the cooler's massive overhang it did sit really close to the board's NB cooler and it was a little trouble to get the 8-pin and CPU fan connectors hooked up but wasn't too much of a prob to do.

Since this board isn't a great OC'er I coudn't really push the CPU hard like I wanted but the temps it showed during the run at least showed it as being capable - I mean if it can keep a Thuban with six cores cool enough it should have no problem with a dual core, provided it doesn't run into a thermal spike due to excessive CPU voltages.