You really dont want to exceed the 1.36v. Once you get beyond that point, not only will there be more heat but your also getting into the danger area, especially for 24/7 use.
It also gets to the point that diminished returns grow much more rapidly.
What I would do, is stay around 1.28v or maybe 1.3v. This is a good area for these CPUs IMHO for a 24/7 OC, without being to hard on them.
Just set the RAM to run as slow as it will allow you to.
Then slowly start bumping up the FSB 5mhz at a time until you Blue Screen, or Windows will no longer boot. Sometimes you can get into Windows and then crash right after the desktop comes up.
Once any of these things happen, you know thats the CPU wall at that voltage.
So if you do not want to increase voltage anymore, drop the FSB speed about 10mhz from the time it blue screened and start testing.
If it fails a stress test, drop the FSB a bit and try again.
Once the CPU seems stable enough, set your RAM.
Id just set the RAM to run as close to spec as possible, or little over.
Just keep a close eye on your temps.
In this voltage range, I think 3.0 is easily achieved.
Although I do not know much about that CPU in particular, most Intel CPUs can do a 20-25% OC fairly well.
So I would guess 3.2Ghz would easily achieved, with proper cooling.
But keep in mind, how well that CPU can OC will depend on the chip itself, cooling, RAM, and how well your motherboard itself can deal with OCing.
You just need to find a place where its all happy together. It may take some time.
Short runs of Prime for an hour or 2 are OK for a quick test,as a very unstable OC will have issues in that time.
But that doesn't mean the OC stable, just that your getting close.
Once you think youve got everything sorted, youll want a Prime run of 10hrs at least to be sure all is OK. If it can do that error free, you can be fairly ceratin you have a stable OC.