There are 2 Q6600. The older SL9UM B3 stepping which runs hot and doesn't overclock well. And the SLACR G0 stepping which is better.
You didn't say what MB you have. But if it supports 1333fsb CPUs and you have a SLACR CPU the classic OC is the tape mod to 3 GHz at stock Voltage.
The 2nd photo here is all you have to do..http://www.tomshardware.com/answers/id-2125877/tape-mod-bsel-mod-intel-q6600.html