You'll have to try it, the stock coolers aren't very good. My E8500 is running much faster than that, but I have an aftermarket cooler on it. I did have occasion to mess with an E6850 not long ago, and I noticed that with the stock cooler running at stock speeds, its temps were higher than the temps for my E8500 at 3.8GHz.
Yeah the E6xxx series is 65nm fabrication while the E8xxx series is 45nm so they run alot cooler. I have a huge ZeroTherm Nirvana NV 120 on my E8400 and only only have a mild overclock but I idle at 25C and hit mid 40s under load. 3.6 is only a mild overclock for this CPU and it will do it on stock voltage so he should be well within the limits with a stock cooler if he has decent case cooling.