i overclocked my e6420 with that board and it hit 3.5 GHZ.
It depends on your cooling, your cpu, and some other parts of your
system(e.g. ram) how well you will be able to overclock.
If you could post your specs, that would really help.
I used some parts of this guide from another forum to get it started:
http://www.hardforum.com/showthread.php?t=1169366
You should also have a look at this guide:
http://www.ocforums.com/showthread.php?t=515316
I am not sure about the vdroop with this board.
If you really want to be sure, you will have to measure it at the motherboard itself.
I pushed my cored2duo up to 1.475 volt(in the bios) and it did ran stable with 3.5 GHZ.
Maybe someone with quad experience can help you out with the voltages.
Do not forget to run some benchies at stock speed to compare it with you oc result.
Anyway...good luck with your overclock and
to the forums!!!