I'm probably one of the least experienced overclockers around here but I think this would be difficult to tell for even an experienced OC'er.
I've seen these P4s being pushed to 5.4Ghz before but that was extreme.
Personally being an amateur overclocker, i'd be happy getting to 3.2 / 3.4 kind of area.
But a lot depends on the options in your mobo bios