E6600 here, (basically the same cpu, just one stepping before), running 400x8.
there is NO reason why you should not have OC your cpu already; shame on you!!
no srsly, go get that extra power, 3.6 should be easy for you.
FYI i have 1.38 V on the cpu and my cheap ArticPro 7 (now CM 212) never complained - NEVER had dangerous temps.
besides, gigabyte board.. it's just begging to be OCd
Good air cooler with a high end Core 2 Duo and a Gigabyte board is overclocking heaven. Back when my E6600 and GA-P35C-DS3R were new, they were absolute monsters. 3.5 GHz dual core five years ago was pretty damn nice.